[clang] Add AST matcher for block expressions 🔍

Summary:
This change adds a new AST matcher for block expressions.

Test Notes:
Ran the clang unit tests.

Reviewers: aaron.ballman

Reviewed By: aaron.ballman

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D55546

llvm-svn: 349004
diff --git a/clang/docs/LibASTMatchersReference.html b/clang/docs/LibASTMatchersReference.html
index 0a8a5a9..28017ca 100644
--- a/clang/docs/LibASTMatchersReference.html
+++ b/clang/docs/LibASTMatchersReference.html
@@ -707,6 +707,14 @@
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('blockExpr0')"><a name="blockExpr0Anchor">blockExpr</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1BlockExpr.html">BlockExpr</a>&gt;...</td></tr>
+<tr><td colspan="4" class="doc" id="blockExpr0"><pre>MAtches a reference to a block.
+
+Example: matches "^{}":
+  void f() { ^{}(); }
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('breakStmt0')"><a name="breakStmt0Anchor">breakStmt</a></td><td>Matcher&lt;<a href="https://clang.llvm.org/doxygen/classclang_1_1BreakStmt.html">BreakStmt</a>&gt;...</td></tr>
 <tr><td colspan="4" class="doc" id="breakStmt0"><pre>Matches break statements.