Convert terminology in the Lexer from 'instantiate' and variants to
'expand'. Also update the public API it provides to the new term, and
propagate that update to the various clients.

No functionality changed.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@135138 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed