feat: extract wordchars from lunr-languages

[dhdaines]

See #149 (doesn't fix the whole thing)

[dhdaines]

Note also that you could also just add {r'\w'} to all_word_characters in the same way as you do for the default pipeline.

[dhdaines]

In actual fact we should add \w to them, because otherwise they will remove numbers at the end of search terms, which is almost certainly not what you want for a lot of applications! But... this is not bug-compatible with lunr-languages, so it might just need a documented workaround.

[dhdaines]

You may not really want to do this, it seems the trimmers in lunr-languages are full of weird junk: MihaiValentin/lunr-languages#66

[dhdaines]

Hmm. It turns out, actually, that lunr-languages code is generated programmatically as well. So it doesn't make a lot of sense to parse it to create these. I'm closing this PR and will come up with a better way to do this.