minor #11623 Deprecate the templating.* options of FrameworkBundle (javiereguiluz)

This PR was squashed before being merged into the 4.3 branch (closes #11623).

Discussion
----------

Deprecate the templating.* options of FrameworkBundle

We're correctly removing them in 5.0 (#11621) but we forgot to add the deprecation notice in 4.3.

Commits
-------

29b46ec Deprecate the templating.* options of FrameworkBundle

Author: javiereguiluz

reference/configuration/framework.rst

@@ -1878,6 +1878,12 @@ package:
 templating
 ~~~~~~~~~~
 
+.. deprecated:: 4.3
+
+    The integration of the Templating component in FrameworkBundle has been
+    deprecated since version 4.3 and will be removed in 5.0. That's why all the
+    configuration options defined under ``framework.templating`` are deprecated too.
+
 .. _reference-templating-form:
 
 form