[clang] Make sure codecompletion is called for calls even when inside a token.

Summary:
Currently CodeCompleteCall only gets called after a comma or parantheses. This
patch makes sure it is called even at the cases like:
```foo(1^);```

Reviewers: ilya-biryukov, ioeric, hokein

Reviewed By: ilya-biryukov

Subscribers: MaskRay, jkorous, arphaman, cfe-commits

Differential Revision: https://reviews.llvm.org/D51038

llvm-svn: 341824
diff --git a/clang/lib/Sema/CodeCompleteConsumer.cpp b/clang/lib/Sema/CodeCompleteConsumer.cpp
index c7d4fc4..226257d 100644
--- a/clang/lib/Sema/CodeCompleteConsumer.cpp
+++ b/clang/lib/Sema/CodeCompleteConsumer.cpp
@@ -619,6 +619,10 @@
       OS << "<#" << C.Text << "#>";
       break;
 
+    // FIXME: We can also print optional parameters of an overload.
+    case CodeCompletionString::CK_Optional:
+      break;
+
     default: OS << C.Text; break;
     }
   }