Parse bare dyn types with leading lifetime
TIL types may start with a lifetime identifier e.g. `type A = 'static + Trait;`. When parsing types, leading lifetime followed by a plus sign should be parsed as a bare dyn type rather than a generic lifetime argument or error type (which is what we produce today).
Although it's no longer accepted since Rust 2021, it wouldn't hurt to support this obsolete syntax.
Provide links to locally built documentation for `experimental/externalDocs`
This pull request addresses issue #12867, which requested the ability to provide links to locally built documentation when using the "Open docs for symbol" feature. Previously, rust-analyzer always used docs.rs for this purpose. With these changes, the feature will provide both web (docs.rs) and local documentation links without verifying their existence.
Changes in this PR:
- Added support for local documentation links alongside web documentation links.
- Added `target_dir` path argument for external_docs and other related methods.
- Added `sysroot` argument for external_docs.
- Added `target_directory` path to `CargoWorkspace`.
API Changes:
- Added an experimental client capability `{ "localDocs": boolean }`. If this capability is set, the `Open External Documentation` request returned from the server will include both web and local documentation links in the `ExternalDocsResponse` object.
Here's the `ExternalDocsResponse` interface:
```typescript
interface ExternalDocsResponse {
web?: string;
local?: string;
}
```
By providing links to both web-based and locally built documentation, this update improves the developer experience for those using different versions of crates, git dependencies, or local crates not available on docs.rs. Rust-analyzer will now provide both web (docs.rs) and local documentation links, leaving it to the client to open the desired link. Please note that this update does not perform any checks to ensure the validity of the provided links.
