Add objcImplementationDecl matcher

Summary:
Add the `objcImplementationDecl` matcher. See related: D30854

Tested with:

```
./tools/clang/unittests/ASTMatchers/ASTMatchersTests
```

Reviewers: aaron.ballman, compnerd, alexshap

Reviewed By: aaron.ballman

Subscribers: klimek, cfe-commits

Differential Revision: https://reviews.llvm.org/D37643

llvm-svn: 312889
diff --git a/clang/docs/LibASTMatchersReference.html b/clang/docs/LibASTMatchersReference.html
index ac90c1e..11006bb 100644
--- a/clang/docs/LibASTMatchersReference.html
+++ b/clang/docs/LibASTMatchersReference.html
@@ -346,6 +346,15 @@
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt;</td><td class="name" onclick="toggle('objcImplementationDecl0')"><a name="objcImplementationDecl0Anchor">objcImplementationDecl</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1ObjCImplementationDecl.html">ObjCImplementationDecl</a>&gt;...</td></tr>
+<tr><td colspan="4" class="doc" id="objcImplementationDecl0"><pre>Matches Objective-C implementation declarations.
+
+Example matches Foo
+  @implementation Foo
+  @end
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt;</td><td class="name" onclick="toggle('objcInterfaceDecl0')"><a name="objcInterfaceDecl0Anchor">objcInterfaceDecl</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1ObjCInterfaceDecl.html">ObjCInterfaceDecl</a>&gt;...</td></tr>
 <tr><td colspan="4" class="doc" id="objcInterfaceDecl0"><pre>Matches Objective-C interface declarations.