move diagnostic insertion methods to be free methods instead of
in the DiagnosticInfo class.  This requires marking them as taking
a const DiagnosticInfo, which is bogus (they logically mutate DI), 
but works with the C++ type system.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@59797 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed