Presentation issues in FilteredAlignment

[Anaphory]

The core code to parse ranges in filtered alignments is https://github.com/CompEvol/beast2/blob/1ba8d2bff70d4fe69b355c2c3670f32295a88e6e/src/beast/evolution/alignment/FilteredAlignment.java#L100-L107

In that code, the comment uses a forward slash, but the code splits according to a backward slash.

            // range, e.g. 1-100/3

The help string also uses a backward slash (even though only in one small uncommented example),

https://github.com/CompEvol/beast2/blob/1ba8d2bff70d4fe69b355c2c3670f32295a88e6e/src/beast/evolution/alignment/FilteredAlignment.java#L19-L25

which gets mangled into a non-printable character in the documentation.

If someone were to touch this section of code because I point to it (which is not important, it's just a display thing, after all), might it make sense to systematically use regexes with capturing groups instead of the current mix of regexes, substrings, and splits?