10877: feat: make hightlighting linear r=matklad a=matklad
In https://youtu.be/qvIZZf5dmTE, we've noticed that AstIdMap does a
linear lookup when going from SyntaxNode to Id. This leads to
accidentally quadratic overall performance. Replace linear lookup with a
O(1) hashmap lookup.
Future work: don't duplicate `SyntaxNodePtr` in `AstIdMap` and switch to
"call site dependency injection" style storage (eg, store a
`HashSet<ErasedFileAstId>`).
See the explanation of the work here on YouTube :-)
As you can see from then benchmark results, this doesn't actually make analysis stats fastre. I am a bit mystified as to why this is happening to be honest.
Baseline
```
Database loaded: 598.40ms, 304minstr, 118mb (metadata 390.57ms, 21minstr, 841kb; build 111.31ms, 8764kinstr, -214kb)
crates: 39, mods: 824, decls: 18647, fns: 13910
Item Collection: 9.70s, 75ginstr, 377mb
exprs: 382426, ??ty: 387 (0%), ?ty: 285 (0%), !ty: 145
Inference: 43.16s, 342ginstr, 641mb
Total: 52.86s, 417ginstr, 1018mb
```
This PR:
```
Database loaded: 626.34ms, 304minstr, 118mb (metadata 416.26ms, 21minstr, 841kb; build 113.67ms, 8750kinstr, -209kb)
crates: 39, mods: 824, decls: 18647, fns: 13910
Item Collection: 10.16s, 75ginstr, 389mb
exprs: 382426, ??ty: 387 (0%), ?ty: 285 (0%), !ty: 145
Inference: 44.51s, 342ginstr, 644mb
Total: 54.67s, 417ginstr, 1034mb
```
I think we probably should merge the first commit here, but not the second.
Co-authored-by: Aleksey Kladov <aleksey.kladov@gmail.com>
9946def7e2