Highlight the offending function parameter when the format_arg argument refers to an invalid function parameter type.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214722 91177308-0d34-0410-b5e6-96231b3b80d8
Highlight the offending function parameter when the format argument refers to an invalid function parameter type.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214723 91177308-0d34-0410-b5e6-96231b3b80d8