Update documentation format guide

contributing/documentation/format.rst

@@ -24,12 +24,11 @@ tutorial and the `reStructuredText Reference`_.
     * Lists start at the beginning of a line (no indentation is allowed);
     * Inline code blocks use double-ticks (````like this````).
 
-Sphinx
-------
+Custom reStructuredText Directives
+----------------------------------
 
-Sphinx_ is a build system that provides tools to create documentation from
-reStructuredText documents. As such, it adds new directives and interpreted text
-roles to the standard reStructuredText markup. Read more about the `Sphinx Markup Constructs`_.
+Symfony Docs include custom directives on top of the standard reStructuredText
+to suit our needs.
 
 Syntax Highlighting
 ~~~~~~~~~~~~~~~~~~~
@@ -45,9 +44,9 @@ change it with the ``code-block`` directive:
 
 .. note::
 
-    Besides all of the major programming languages, the syntax highlighter
-    supports all kinds of markup and configuration languages. Check out the
-    list of `supported languages`_ on the syntax highlighter website.
+    Code highlighting is support for all the programming languages commonly used
+    in Symfony Docs: ``yaml``, ``xml``, ``twig``, ``html``, ``js``, ``json``,
+    ``text``, ``bash``, ``diff``, etc.
 
 .. _docs-configuration-blocks:
 
@@ -281,9 +280,6 @@ example, if Symfony 6.0 were released today, 5.0 to 5.4 ``versionadded`` and
 ``deprecated`` tags would be removed from the new ``6.0`` branch.
 
 .. _reStructuredText: https://docutils.sourceforge.io/rst.html
-.. _Sphinx: https://www.sphinx-doc.org/
 .. _`Symfony documentation`: https://github.com/symfony/symfony-docs
 .. _`reStructuredText Primer`: https://www.sphinx-doc.org/en/master/usage/restructuredtext/basics.html
 .. _`reStructuredText Reference`: https://docutils.sourceforge.io/docs/user/rst/quickref.html
-.. _`Sphinx Markup Constructs`: https://www.sphinx-doc.org/en/1.7/markup/index.html
-.. _`supported languages`: https://pygments.org/languages/