Switch the diagnostic messages about macros to use the terms 'expanded'
and 'expansions' rather than 'instantiated' and 'contexts'.

This is the first of several patches migrating Clang's terminology
surrounding macros from 'instantiation' to 'expansion'.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@135135 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed