PHPDoc: Replace non-existing param type const with string

Summary:
`const` is not a valid type. See https://docs.phpdoc.org/guide/references/phpdoc/types.html and https://docs.phpdoc.org/guide/references/phpdoc/tags/return.html.
Thus set the param type to `string` and get a few less errors reported by PHPStan.

Test Plan: Read docs; run static code analysis.

Reviewers: O1 Blessed Committers, valerio.bozzolan

Reviewed By: O1 Blessed Committers, valerio.bozzolan

Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Differential Revision: https://we.phorge.it/D25938

src/applications/auth/engine/PhabricatorAuthSessionEngine.php

···
    * loading context. This prevents use of a Conduit sesssion as a Web
    * session, for example.
    *
-   * @param const $session_type The type of session to load.
+   * @param string $session_type Constant of the type of session to load.
    * @param string $session_token The session token.
    * @return PhabricatorUser|null
    * @task use
···
    * You can configure the maximum number of concurrent sessions for various
    * session types in the Phabricator configuration.
    *
-   * @param   const     $session_type Session type constant (see
+   * @param   string    $session_type Session type constant (see
    *                    @{class:PhabricatorAuthSession}).
    * @param   phid|null $identity_phid Identity to establish a session for,
    *                    usually a user PHID. With `null`, generates an

src/applications/differential/constants/DifferentialReviewerStatus.php

···
    * will attempt to update you to both "commented" and "accepted". We want
    * "accepted" to win, because it's the stronger of the two.
    *
-   * @param   const $constant Reviewer status constant.
-   * @return  int   Relative strength (higher is stronger).
+   * @param   string $constant Reviewer status constant.
+   * @return  int    Relative strength (higher is stronger).
    */
   public static function getStatusStrength($constant) {
     $map = array(

src/applications/harbormaster/constants/HarbormasterBuildStatus.php

···
   /**
    * Get a human readable name for a build status constant.
    *
-   * @param  const $status Build status constant.
+   * @param  string $status Build status constant.
    * @return string Human-readable name.
    */
   public static function getBuildStatusName($status) {

src/applications/metamta/storage/PhabricatorMetaMTAMail.php

···
    * These tags are used to allow users to opt out of receiving certain types
    * of mail, like updates when a task's projects change.
    *
-   * @param list<const> $tags
+   * @param list<string> $tags Tag constants.
    * @return $this
    */
   public function setMailTags(array $tags) {

src/applications/people/storage/PhabricatorUser.php

···
   /**
    * Test if a given setting is set to a particular value.
    *
-   * @param const $key Setting key.
+   * @param string $key Setting key constant.
    * @param wild $value Value to compare.
    * @return bool True if the setting has the specified value.
    * @task settings

src/applications/policy/interface/PhabricatorExtendedPolicyInterface.php

···
    *     // ...
    *   );
    *
-   * @param const $capability Capability being tested.
+   * @param string $capability Constant of the capability being tested.
    * @param PhabricatorUser $viewer Viewer whose capabilities are being tested.
    * @return list<pair<wild, wild>> List of extended policies.
    */

src/applications/search/engine/PhabricatorApplicationSearchEngine.php

···
    *
    * @param AphrontRequest  $request Request to read user PHIDs from.
    * @param string          $key Key to read in the request.
-   * @param list<const>     $allow_types (optional) Other permitted PHID types.
+   * @param list<string>    $allow_types (optional) Other permitted PHID type
+   *                        constants.
    * @return list<phid>     List of user PHIDs and selector functions.
    * @task read
    */
···
    *
    * @param AphrontRequest  $request Request to read PHIDs from.
    * @param string          $key Key to read in the request.
-   * @param list<const>     $allow_types (optional) List of permitted PHID
-   *                        types.
+   * @param list<string>    $allow_types (optional) List of permitted PHID
+   *                        type constants.
    * @return list<phid>     List of object PHIDs.
    *
    * @task read

src/applications/transactions/editengine/PhabricatorEditEngine.php

···
    * to make Conduit a little easier to use.
    *
    * @param wild $identifier ID, PHID, or monogram.
-   * @param list<const> $capabilities (optional) List of required capability
+   * @param list<string> $capabilities (optional) List of required capability
    *   constants, or omit for defaults.
    * @return object Corresponding editable object.
    * @task load
···
    * Load an object by ID.
    *
    * @param int $id Object ID.
-   * @param list<const> $capabilities (optional) List of required capability
+   * @param list<string> $capabilities (optional) List of required capability
    *   constants, or omit for defaults.
    * @return object|null Object, or null if no such object exists.
    * @task load
···
    * Load an object by PHID.
    *
    * @param phid $phid Object PHID.
-   * @param list<const> $capabilities (optional) List of required capability
+   * @param list<string> $capabilities (optional) List of required capability
    *   constants, or omit for defaults.
    * @return object|null Object, or null if no such object exists.
    * @task load
···
    * Load an object given a configured query.
    *
    * @param PhabricatorPolicyAwareQuery $query Configured query.
-   * @param list<const> $capabilities (optional) List of required capability
+   * @param list<string> $capabilities (optional) List of required capability
    *  constants, or omit for defaults.
    * @return object|null Object, or null if no such object exists.
    * @task load

src/infrastructure/contentsource/PhabricatorContentSource.php

···
   /**
    * Construct a new content source object.
    *
-   * @param const $source The source type constant to build a source for.
-   * @param array $params (optional) Source parameters.
-   * @param bool  $force (optional) True to suppress errors and force
+   * @param string $source The source type constant to build a source for.
+   * @param array  $params (optional) Source parameters.
+   * @param bool   $force (optional) True to suppress errors and force
    *   construction of a source even if the source type is not valid.
    * @return PhabricatorContentSource New source object.
    */

src/infrastructure/customfield/field/PhabricatorCustomField.php

···
   /**
    * Get the Herald value type for the given condition.
    *
-   * @param   const       $condition Herald condition constant.
-   * @return  const|null  Herald value type, or null to use the default.
+   * @param   string       $condition Herald condition constant.
+   * @return  string|null  Herald value type constant, or null to use the
+   *                       default.
    * @task herald
    */
   public function getHeraldFieldValueType($condition) {

src/infrastructure/daemon/workers/query/PhabricatorWorkerTriggerQuery.php

···
    * triggers which have been scheduled to execute. You should not use this
    * ordering when querying for specific triggers, e.g. by ID or PHID.
    *
-   * @param const $order Result order.
+   * @param string $order Result order constant.
    * @return $this
    */
   public function setOrder($order) {

src/infrastructure/edges/editor/PhabricatorEdgeEditor.php

···
    *     provided, `data` will be written.
    *
    * @param phid  $src Source object PHID.
-   * @param const $type Edge type constant.
+   * @param string  $type Edge type constant.
    * @param phid  $dst Destination object PHID.
    * @param map   $options (optional) Options map (see documentation).
    * @return $this
···
    * a remove plus an add is to overwrite.
    *
    * @param phid  $src Source object PHID.
-   * @param const $type Edge type constant.
+   * @param string  $type Edge type constant.
    * @param phid  $dst Destination object PHID.
    * @return $this
    *

src/infrastructure/edges/query/PhabricatorEdgeQuery.php

···
   /**
    * Configure the order edge results are returned in.
    *
-   * @param const $order Order constant.
+   * @param string $order Order constant.
    * @return $this
    *
    * @task config
···
    * use case.
    *
    * @param phid  $src_phid Source PHID.
-   * @param const $edge_type Edge type.
+   * @param string $edge_type Edge type constant.
    * @return list<phid> List of destination PHIDs.
    */
   public static function loadDestinationPHIDs($src_phid, $edge_type) {
···
    * and immediately executes a full query.
    *
    * @param phid  $src_phid Source PHID.
-   * @param const $edge_type Edge type.
+   * @param string  $edge_type Edge type constant.
    * @param phid  $dest_phid Destination PHID.
    * @return wild Edge annotation (or null).
    */

src/infrastructure/query/policy/PhabricatorCursorPagedPolicyAwareQuery.php

···
    * Convenience method for specifying edge logic constraints with a list of
    * PHIDs.
    *
-   * @param const $edge_type Edge constant.
-   * @param const $operator Constraint operator.
+   * @param string $edge_type Edge constant.
+   * @param string $operator Constraint operator.
    * @param list<phid> $phids List of PHIDs.
    * @return $this
    * @task edgelogic

src/infrastructure/storage/lisk/LiskDAO.php

···
   /**
    * Determine the setting of a configuration option for this class of objects.
    *
-   * @param  const  $option_name Option name, one of the CONFIG_* constants.
+   * @param string  $option_name Option name, one of the CONFIG_* constants.
    * @return mixed  Option value, if configured (null if unavailable).
    *
    * @task   config
···
   /**
    * Internal implementation of INSERT and REPLACE.
    *
-   * @param  const $mode Either "INSERT" or "REPLACE", to force the desired
+   * @param string $mode Either "INSERT" or "REPLACE", to force the desired
    *   mode.
    * @return $this
    *