Merge pull request #28862 from veprbl/doc_fix

small documentation fixes

.github/CONTRIBUTING.md

···
   Examples:
 
   * nginx: init at 2.0.1
-  * firefox: 3.0 -> 3.1.1
+  * firefox: 54.0.1 -> 55.0
   * nixos/hydra: add bazBaz option
   
     Dual baz behavior is needed to do foo.

doc/coding-conventions.xml

···
   <varlistentry>
     <term>If it’s a (set of) <emphasis>tool(s)</emphasis>:</term>
     <listitem>
-      <para>(A tool is a relatively small program, especially one intented
+      <para>(A tool is a relatively small program, especially one intended
       to be used non-interactively.)</para>
       <variablelist>
         <varlistentry>
···
 </section>
 <section xml:id="sec-sources"><title>Fetching Sources</title>
   <para>There are multiple ways to fetch a package source in nixpkgs. The
-    general guidline is that you should package sources with a high degree of
+    general guideline is that you should package sources with a high degree of
     availability. Right now there is only one fetcher which has mirroring
     support and that is <literal>fetchurl</literal>. Note that you should also
     prefer protocols which have a corresponding proxy environment variable.

doc/languages-frameworks/python.md

···
 e.g. the test runner, should be added to `buildInputs`.
 
 By default `meta.platforms` is set to the same value
-as the interpreter unless overriden otherwise.
+as the interpreter unless overridden otherwise.
 
 ##### `buildPythonPackage` parameters
 

doc/languages-frameworks/rust.md

···
 `nix-shell -p rustStable.rustc -p rustStable.cargo`.
 
 There are also `rustBeta` and `rustNightly` package sets available.
-These are not updated very regulary. For daily builds use either rustup from
+These are not updated very regularly. For daily builds use either rustup from
 nixpkgs or use the [Rust nightlies overlay](#using-the-rust-nightlies-overlay).
 
 ## Packaging Rust applications

doc/submitting-changes.xml

···
 
 <listitem>
 <para>
-<command>firefox: 3.0 -> 3.1.1</command>
+<command>firefox: 54.0.1 -> 55.0</command>
 </para>
 </listitem>