[Doc parsing] Provide diagnostics for unknown documentation 
commands. // rdar://12381408

llvm-svn: 181071
diff --git a/clang/test/Sema/warn-documentation.cpp b/clang/test/Sema/warn-documentation.cpp
index 0132ef2..b3ab019 100644
--- a/clang/test/Sema/warn-documentation.cpp
+++ b/clang/test/Sema/warn-documentation.cpp
@@ -892,10 +892,10 @@
 
 // We used to crash on this.
 
+// expected-warning@+1 {{unknown command tag name}}
 /// aaa \unknown aaa \unknown aaa
 int test_nocrash9;
 
-
 // We used to crash on this.  PR15068
 
 // expected-warning@+2 {{empty paragraph passed to '@param' command}}