Add context-sensitive field name completion to Ada parser
This updates the Ada expression parser to implement context-sensitive
field name completion. This is PR ada/28727.
This is somewhat complicated due to some choices in the Ada lexer --
it chooses to represent a sequence of "."-separated identifiers as a
single token, so the parser must partially recreate the completer's
logic to find the completion word boundaries.
Despite the minor warts in this patch, though, it is a decent
improvement. It's possible that the DWARF reader rewrite will help
fix the package completion problem pointed out in this patch as well.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28727
6 files changed
