Apply final suggestions from probinson for this patch series plus a
few more tweaks:
- Improve various docs, for MatchType in particular.
- Rename some members of MatchType. The main problem was that the term "final match" became a misnomer when CHECK-COUNT-<N> was created.
- Split InputStartLine, etc. declarations into multiple lines.
This patch doesn't necessarily require a review, but I wanted to put it in phabricator for safe keeping while waiting for D53899 to be accepted.