feat(syntax): support the new oneliner version

[Akuukis]

Please merge an update for the beancount plugin "oneliner". See the improved syntax highlights below (includes PRs #92 #93 #94)

Ayu Mirage (before & after)

Monokai Classic (before & after)

Night Owl Dark (before & after)

[Lencerf]

Hi Akuukis, thanks for the PR, have you ever sent your plug-in to upstream beancount?
Personally I am not a fan of writing everything in a single line.

Since this change is probably just for your own use case, I'd prefer not changing beancount.tmLanguage.

Maybe the acceptable way is,

• send your plugin to upstream, make your oneline syntax part of the official beancount syntax

Or,

• add a new language called beancount-oneline, add a beancount-oneline.tmLanguage, and define your syntax there.

[Akuukis]

Ok, extracted to a separate syntax file!

As per upstream, from the design docs Blais has written I clearly see he wants the beancount core lean and small, and thus I don't believe that such shorthands like oneliner (or my other plugins) have a place in core. But maybe there's a difference between "official syntax" and "code lives in core" and it's worth asking for, who knows, maybe that opens up possibilities for even nicer syntax and therefore a way for proper auto-completes.