Remove completion limit for trait importing method completions
Fixes https://github.com/rust-lang/rust-analyzer/issues/16075
The < 3 char limit never applied to methods and the amount of completions generated due this is not absolutely massive as not all traits in a project are ever applicable so there is little reason to employ the limit here. Especially as it limits the number of traits we consider, not items (after my changes yesterday), and the number of traits is not the slowing factor here. Tested this in r-a where we have ~800 traits project wide and even when ~260 are applicable there was no noticable slow down from it.
Further tuning of the Gentoo installation instructions.
Based on feedback from the Gentoo repository maintainer, addition of the possibility to install rust-analyzer via rustup.
internal: Move query limits to the caller
Prior we calculated up to `limit` entries from a query, then filtered from that leaving us with less entries than the limit in some cases (which might give odd completion behavior due to items disappearing). This changes it so we filter before checking the limit.
Give a userful error when rustc cannot be found in explicit sysroot
Somehow r-a believed that my sysroot was something weird with no rustc. Probably a me issue, but it was impossible to diagnose since r-a just gave me a plain "No such file or directory". Adding this error makes it clear what happened and allows diagnosing the problem.
internal: Switch to `expected.assert_eq` for `ide` tests
This PR switches from `assert_debug_eq` to `assert_eq` and only compares parts of the result and not the whole. The aim is to only compare parts which are relevant to the test and also make it more readable.
Part of #14268.
## Questions
- [x] Can I use `Vec`? If not, what is the alternative?
I assume I cannot because of: c3a00b5468/docs/dev/architecture.md (L413)
- [x] Should I group it by file, as proposed by Lukas?
```
file_id 1:
source_file_edits:
- Indel { insert: "foo2", delete: 4..7 }
file_id 2:
file_system_edits:
MoveFile AnchoredPathBuf { anchor: FileId(2), path: "foo2.rs", }
```
- [x] Is it okay to ignore `CreateFile` events? They do not have a FileId, which would be problematic, but they do not occur in the existing tests, so I marked them as `unreachable!()` so far.
