Fix bugs seen by _build/build.php diagnostics in 4.4

Author: MarkPedron

form/bootstrap4.rst

@@ -77,7 +77,7 @@ If you prefer to apply the Bootstrap styles on a form to form basis, include the
         {{ form(form) }}
     {% endblock %}
 
-.. _reference-forms-bootstrap-error-messages:
+.. _reference-forms-bootstrap4-error-messages:
 
 Error Messages
 --------------

index.rst

@@ -69,9 +69,9 @@ Components
 .. toctree::
     :hidden:
 
-    components/index
+    components/
 
-Read the :doc:`Components </components/index>` documentation.
+Read the :doc:`Components </components/>` documentation.
 
 Reference Documents
 -------------------

testing.rst

@@ -523,10 +523,6 @@ The full signature of the ``request()`` method is::
 
 This allows you to create all types of requests you can think of:
 
-.. contents::
-    :local:
-    :depth: 1
-
 .. tip::
 
     The test client is available as the ``test.client`` service in the
@@ -671,10 +667,6 @@ Interacting with the Response
 Like a real browser, the Client and Crawler objects can be used to interact
 with the page you're served:
 
-.. contents::
-    :local:
-    :depth: 1
-
 .. _testing-links:
 
 Clicking on Links
@@ -815,10 +807,6 @@ check anything you want.
 
 However, Symfony provides useful shortcut methods for the most common cases:
 
-.. contents::
-    :local:
-    :depth: 1
-
 .. versionadded:: 4.3
 
     The shortcut methods for assertions using ``WebTestCase`` were introduced