Switch syntect regex engine over to onig and add newer JS syntax file

[Nemo157]

Changing the engine ~halves the time it takes to render readmes. Timings from rendering all readmes in the database dump from a couple years ago:

before: rendered 154040/154040 in 1.268288ms on average
after: rendered 154040/154040 in 583.846µs on average

It's also required to support the JavaScript (Babel) syntax file. This syntax doesn't run into the issue mentioned in #1942, but as I mention there I don't think this is going to be the only trigger so I want to see if there's something else easy we could do to avoid it completely.

(Draft because I'm still rebuilding my local server to actually check that the JS syntax looks good when rendered).

[jsha]

What are the after timings across the database dump if you collect the worst-case runtime on any of the READMEs?

[syphar]

@Nemo157 @jyn514 is this ready to be merged?

I'm confused by the approval & the draft state of this PR :)

[Nemo157]

The code is done, but I wanted to look at the actual UI before undrafting. I was having issues rebuilding the docker image (for some reason Ubuntu's update server was 403ing me), now that's been rebuilt but that also updated the database image which broke, so I need to figure out how to revert/migrate that sometime tonight.

docsrs-db-1  | 2022-12-05 10:25:14.779 UTC [1] FATAL:  database files are incompatible with server
docsrs-db-1  | 2022-12-05 10:25:14.779 UTC [1] DETAIL:  The data directory was initialized by PostgreSQL version 12, which is not compatible with this version 15.1.

[Nemo157]

Got my local server running and check a couple JS files, they render just fine still.