minor #17480 Static code analysis (Koc)

This PR was merged into the 2.3 branch.

Discussion
----------

Static code analysis

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Things that done:
* fix case in method calls
* removed unused imports
* use shorter concat where it possible
* optimize some css
* removed duplicated array keys
* removed redurant return statements
* removed one-time variables
* do not pass arguments that not used in functions

Commits
-------

8db691a Static code analysis

Author: fabpot

Adapter/AbstractFindAdapter.php

@@ -94,7 +94,7 @@ public function searchInDirectory($dir)
         $command->setErrorHandler(
             $this->ignoreUnreadableDirs
                 // If directory is unreadable and finder is set to ignore it, `stderr` is ignored.
-                ? function ($stderr) { return; }
+                ? function ($stderr) { }
                 : function ($stderr) { throw new AccessDeniedException($stderr); }
         );