[clang-tidy] When emitting header guard fixes bundle all fix-its into one
warning.

Before we would emit two warnings if the header guard was wrong and the comment
on a trailing #endif also needed fixing.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@217890 91177308-0d34-0410-b5e6-96231b3b80d8