KUnit: Docs: style: fix some Kconfig example issues

Fix the Kconfig example to be closer to Kconfig coding style.

Also add punctuation and a trailing slash ('/') to a sub-directory
name -- this is how the text mostly appears in other Kconfig files.

Signed-off-by: Randy Dunlap <[e-mail]>
Cc: David Gow <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: Shuah Khan <[e-mail]>
Cc: Shuah Khan <[e-mail]>
Cc: Brendan Higgins <[e-mail]>
Reviewed-by: David Gow <[e-mail]>
Signed-off-by: Shuah Khan <[e-mail]>

Documentation/dev-tools/kunit/style.rst

···
 
 .. code-block:: none
 
-        config FOO_KUNIT_TEST
-                tristate "KUnit test for foo" if !KUNIT_ALL_TESTS
-                depends on KUNIT
-                default KUNIT_ALL_TESTS
-                help
-                    This builds unit tests for foo.
+	config FOO_KUNIT_TEST
+		tristate "KUnit test for foo" if !KUNIT_ALL_TESTS
+		depends on KUNIT
+		default KUNIT_ALL_TESTS
+		help
+		  This builds unit tests for foo.
 
-                    For more information on KUnit and unit tests in general, please refer
-                    to the KUnit documentation in Documentation/dev-tools/kunit
+		  For more information on KUnit and unit tests in general, please refer
+		  to the KUnit documentation in Documentation/dev-tools/kunit/.
 
-                    If unsure, say N
+		  If unsure, say N.
 
 
 Test File and Module Names