[clang-format] structured binding in range for detected as Objective C

Summary:
Sometime after 6.0.0 and the current trunk 9.0.0 the following code would be considered as objective C and not C++

Reported by: https://twitter.com/mattgodbolt/status/1096188576503644160

$ clang-format.exe test.h
Configuration file(s) do(es) not support Objective-C: C:\clang\build\.clang-format

--- test.h --
```

std::vector<std::pair<std::string,std::string>> C;

void foo()
{
   for (auto && [A,B] : C)
   {
       std::string D = A + B;
   }
}
```
The following code fixes this issue of incorrect detection

Reviewers: djasper, klimek, JonasToth, reuk

Reviewed By: klimek

Subscribers: cfe-commits

Tags: #clang-tools-extra

Differential Revision: https://reviews.llvm.org/D59546

llvm-svn: 356575