Merge branch '4.4' into 5.1

* 4.4:
  Tweak
  Update validation.rst
  update building locally without docker docs

Author: javiereguiluz

contributing/documentation/overview.rst

@@ -273,7 +273,8 @@ If you don't use Docker, follow these steps to build the docs locally:
 
    .. code-block:: terminal
 
-        $ pip install sphinx~=1.3.0 git+https://github.com/fabpot/sphinx-php.git
+        $ cd _build/
+        $ pip install -r .requirements.txt
 
 #. Run the following command to build the documentation in HTML format:
 

validation.rst

@@ -119,8 +119,8 @@ following:
 .. index::
    single: Validation; Using the validator
 
-Using the ``validator`` Service
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Using the Validator Service
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Next, to actually validate an ``Author`` object, use the ``validate()`` method
 on the ``validator`` service (which implements :class:`Symfony\\Component\\Validator\\Validator\\ValidatorInterface`).