internal : redesign rust-analyzer::config
This PR aims to cover the infrastructural requirements for the `rust-analyzer.toml` ( #13529 ) issue. This means, that
1. We no longer have a single config base. The once single `ConfigData` has been divided into 4 : A tree of `.ratoml` files, a set of configs coming from the client ( this is what was called before the `CrateData` except that now values do not default to anything when they are not defined) , a set of configs that will reflect what the contents of a `ratoml` file defined in user's config directory ( e.g `~/.config/rust-analyzer/.rust-analyzer.toml` and finally a tree root that is populated by default values only.
2. Configs have also been divided into 3 different blocks : `global` , `local` , `client`. The current status of a config may change until #13529 got merged.
Once again many thanks to `@cormacrelf` for doing all the serde work.
Instead of using `core::fmt::format` to format panic messages, which may in turn
panic too and cause recursive panics and other messy things, redirect
`panic_fmt` to `const_panic_fmt` like CTFE, which in turn goes to
`panic_display` and does the things normally. See the tests for the full
call stack.
internal: Enforce utf8 paths
Cargo already requires this, and I highly doubt r-a works with non-utf8 paths generally either. This just makes dealing with paths a lot easier.
feat: Syntax highlighting improvements
Specifically
- Adds a new `constant` modifier, attached to keyword `const` (except for `*const ()` and `&raw const ()`), `const` items and `const` functions
- Adds (or rather reveals) `associated` modifier for associated items
- Fixes usage of the standard `static` modifier, now it acts like `associated` except being omitted for methods.
- Splits `SymbolKind::Function` into `Function` and `Method`. We already split other things like that (notable self param from params), so the split makes sense in general as a lot special cases around it anyways.
fix: Fix wrong where clause rendering on hover
We were not accounting for proper newline indentation in some places making the hover look weird (or just straight up wrong for type aliases)
internal: Compress file text using LZ4
I haven't tested properly, but this roughly looks like:
```
1246 MB
59mb 4899 FileTextQuery
1008 MB
20mb 4899 CompressedFileTextQuery
555kb 1790 FileTextQuery
```
We might want to test on something more interesting, like `bevy`.
