docs: Fix up HTML links to proper reST links.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@171382 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/LanguageExtensions.rst b/docs/LanguageExtensions.rst
index c3e2c83..be6ea52 100644
--- a/docs/LanguageExtensions.rst
+++ b/docs/LanguageExtensions.rst
@@ -87,8 +87,8 @@
 ``cxx_`` or ``objc_``.
 
 Another use of ``__has_feature`` is to check for compiler features not related
-to the language standard, such as e.g. `AddressSanitizer
-<AddressSanitizer.html>`_.
+to the language standard, such as e.g. :doc:`AddressSanitizer
+<AddressSanitizer>`.
 
 If the ``-pedantic-errors`` option is given, ``__has_extension`` is equivalent
 to ``__has_feature``.
@@ -925,8 +925,8 @@
 Automatic reference counting
 ----------------------------
 
-Clang provides support for `automated reference counting
-<AutomaticReferenceCounting.html>`_ in Objective-C, which eliminates the need
+Clang provides support for :doc:`automated reference counting
+<AutomaticReferenceCounting>` in Objective-C, which eliminates the need
 for manual ``retain``/``release``/``autorelease`` message sends.  There are two
 feature macros associated with automatic reference counting:
 ``__has_feature(objc_arc)`` indicates the availability of automated reference
@@ -934,6 +934,8 @@
 automated reference counting also includes support for ``__weak`` pointers to
 Objective-C objects.
 
+.. _objc-fixed-enum:
+
 Enumerations with a fixed underlying type
 -----------------------------------------
 
@@ -1010,8 +1012,8 @@
 Object Literals and Subscripting
 --------------------------------
 
-Clang provides support for `Object Literals and Subscripting
-<ObjectiveCLiterals.html>`_ in Objective-C, which simplifies common Objective-C
+Clang provides support for :doc:`Object Literals and Subscripting
+<ObjectiveCLiterals>` in Objective-C, which simplifies common Objective-C
 programming patterns, makes programs more concise, and improves the safety of
 container creation.  There are several feature macros associated with object
 literals and subscripting: ``__has_feature(objc_array_literals)`` tests the