newline after 1-line indented code inside blocks, and forcing files to
have a trailing newline. The trailing newline thing created a lot of
spurious changes.
better path going forward to handling upgrades. Old syntax files will
stick around for compatibility purposes. Old syntax can be parsed into
valid syntax trees via the old syntax (.peg) files, and then old syntax
trees should be valid and can be upgraded via the normal code path. This
change has lots of improvements to Nomsu codegen too.
