minor #32993 Turned return type annotations of private methods into php return types (derrabus)

This PR was merged into the 4.4 branch.

Discussion
----------

Turned return type annotations of private methods into php return types

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | N/A
| License       | MIT
| Doc PR        | N/A

As discussed with @nicolas-grekas in symfony/symfony#30323 (comment), this PR attempts to turn `@return` annotations on private methods into return type declarations.

Commits
-------

f54ca001fe Turned return type annotations of private methods into php return types.

Author: nicolas-grekas

FileLocator.php

@@ -76,12 +76,8 @@ public function locate($name, $currentPath = null, $first = true)
 
     /**
      * Returns whether the file path is an absolute path.
-     *
-     * @param string $file A file path
-     *
-     * @return bool
      */
-    private function isAbsolutePath(string $file)
+    private function isAbsolutePath(string $file): bool
     {
         if ('/' === $file[0] || '\\' === $file[0]
             || (\strlen($file) > 3 && ctype_alpha($file[0])

ResourceCheckerConfigCache.php

@@ -144,10 +144,8 @@ public function write($content, array $metadata = null)
 
     /**
      * Gets the meta file path.
-     *
-     * @return string The meta file path
      */
-    private function getMetaFile()
+    private function getMetaFile(): string
     {
         return $this->file.'.meta';
     }