A related test for highlighting YAML currently fails with the
fancy-regex changes, so this simpler test may make it easier to track
down the problem.

Some of the regexes include `$` and expect it to match end of line. In
fancy-regex, `$` means end of text by default. Adding `(?m)` activates
multi-line mode which changes `$` to match end of line.

This fixes a large number of the failed assertions with syntest.

In fancy-regex, POSIX character classes only match ASCII characters.
Sublime's syntaxes expect them to match Unicode characters as well, so
transform them to corresponding Unicode character classes.

With the regex crate and fancy-regex, `^` in multi-line mode also
matches at the end of a string like "test\n". There are some regexes in
the syntax definitions like `^\s*$`, which are intended to match a blank
line only. So change `^` to `\A` which only matches at the beginning of
text.

Note that this wasn't a problem with Oniguruma because it works on UTF-8
bytes, but fancy-regex works on characters.

I think the println! was only there to see the regex that failed to
compile.