[ASTMatcher] Add clang-query disclaimer to two more matchers that take enum

As we have figured out in
https://reviews.llvm.org/D57112
and
https://bugs.llvm.org/show_bug.cgi?id=41176

this kind-of works, but needs special care.

llvm-svn: 356677
diff --git a/clang/docs/LibASTMatchersReference.html b/clang/docs/LibASTMatchersReference.html
index 05f5c1f..10b9ebf 100644
--- a/clang/docs/LibASTMatchersReference.html
+++ b/clang/docs/LibASTMatchersReference.html
@@ -2640,6 +2640,9 @@
 Example: matches the implicit cast around 0
 (matcher = castExpr(hasCastKind(CK_NullToPointer)))
   int *p = 0;
+
+If the matcher is use from clang-query, CastKind parameter
+should be passed as a quoted string. e.g., ofKind("CK_NullToPointer").
 </pre></td></tr>
 
 
@@ -4086,6 +4089,9 @@
   int s = sizeof(x) + alignof(x)
 unaryExprOrTypeTraitExpr(ofKind(UETT_SizeOf))
   matches sizeof(x)
+
+If the matcher is use from clang-query, UnaryExprOrTypeTrait parameter
+should be passed as a quoted string. e.g., ofKind("UETT_SizeOf").
 </pre></td></tr>