feat: TS autocomplete

[benlubas]

Uses Treesitter to find autocompletion suggestions. Has a few impacts:

• we'll no longer incorrectly link to norg in a verbatim or like a code block or something
• now links to line targets like inline <target> with {#|} completions
• {#|} completions will correctly suggest footers and other targets that it wouldn't before

I just pulled the query from core.esupports.hop. We could maybe refactor that out, b/c currently completion requires hop, which is slightly weird. Lmk if I should do that and what helper module you'd like me to use/make.

[vhyrro]

LGTM! I think that the wisest way of handling esupports.hop is to extract the finding logic out into a separate module (e.g. core.links), then having esupports.hop do the actual hopping. Will you want to tackle that in a separate PR?

[benlubas]

Blocked on #1428, but this PR is now updated so it can be merged right after #1428

[vhyrro]

One conflict that needs fixing, you know what to do :p