Merge branch '5.0' into 5.1

* 5.0:
  Update authorization.rst
  Update filesystem.rst
  Update TypeHint Serializer.rst

Author: javiereguiluz

components/filesystem.rst

@@ -193,6 +193,8 @@ of a single file or directory::
     $filesystem->rename('/tmp/processed_video.ogg', '/path/to/store/video_647.ogg');
     // renames a directory
     $filesystem->rename('/tmp/files', '/path/to/store/files');
+    // if the target already exists, a third boolean argument is available to overwrite.
+    $filesystem->rename('/tmp/processed_video2.ogg', '/path/to/store/video_647.ogg', true);
 
 ``symlink``
 ~~~~~~~~~~~

components/security/authorization.rst

@@ -47,7 +47,9 @@ recognizes several strategies:
     grant access if there are more voters granting access than there are denying;
 
 ``unanimous``
-    only grant access if none of the voters has denied access;
+    only grant access if none of the voters has denied access. If all voters
+    abstained from voting, the decision is based on the ``allow_if_all_abstain``
+    config option (which defaults to ``false``).
 
 ``priority``
     grants or denies access by the first voter that does not abstain;

components/serializer.rst

@@ -463,12 +463,12 @@ A custom name converter can handle such cases::
 
     class OrgPrefixNameConverter implements NameConverterInterface
     {
-        public function normalize($propertyName)
+        public function normalize(string $propertyName)
         {
             return 'org_'.$propertyName;
         }
 
-        public function denormalize($propertyName)
+        public function denormalize(string $propertyName)
         {
             // removes 'org_' prefix
             return 'org_' === substr($propertyName, 0, 4) ? substr($propertyName, 4) : $propertyName;