fix: allow new, subsequent `rust-project.json`-based workspaces to get proc macro expansion
As detailed in https://github.com/rust-lang/rust-analyzer/issues/14417#issuecomment-1485336174, `rust-project.json` workspaces added after the initial `rust-project.json`-based workspace was already indexed by rust-analyzer would not receive procedural macro expansion despite `config.expand_proc_macros` returning true. To fix this issue:
1. I changed `reload.rs` to check which workspaces are newly added.
2. Spawned new procedural macro expansion servers based on the _new_ workspaces.
1. This is to prevent spawning duplicate procedural macro expansion servers for already existing workspaces. While the overall memory usage of duplicate procedural macro servers is minimal, this is more about the _principle_ of not leaking processes 😅.
3. Launched procedural macro expansion if any workspaces are `rust-project.json`-based _or_ `same_workspaces` is true. `same_workspaces` being true (and reachable) indicates that that build scripts have finished building (in Cargo-based projects), while the build scripts in `rust-project.json`-based projects have _already been built_ by the build system that produced the `rust-project.json`.
I couldn't really think of structuring this code in a better way without engaging with https://github.com/rust-lang/rust-analyzer/issues/7444.
Implement invocation strategy config
Fixes https://github.com/rust-lang/rust-analyzer/issues/10793
This allows to change how we run build scripts (and `checkOnSave`), exposing two configs:
- `once`: run the specified command once in the project root (the working dir of the server)
- `per_workspace`: run the specified command per workspace in the corresponding workspace
This also applies to `checkOnSave` likewise, though `once_in_root` is useless there currently, due to https://github.com/rust-lang/cargo/issues/11007
This PR will fix some typos detected by [typos].
There are also some other typos in the function names, variable names, and file
names, which I leave as they are. I'm more certain that typos in comments
should be fixed.
[typos]: https://github.com/crate-ci/typos
