Exclude well known names from showing a suggestion in check-cfg

[Urgau]

This PR adds an exclusion for well known names from showing in suggestions of check-cfg/unexpected_cfgs.

Follow-up to #118213 and fixes #118213 (comment).

r? @petrochenkov

[petrochenkov]

I really don't want to merge it like this.
The list should either be filled automatically when we are collecting built-in cfg names, or we should live with these help notes.
@rustbot author

[Urgau]

I've updated the PR to not rely anymore on a hard-coded list and instead have an FxHashSet<Symbol> being dynamically populated from CheckCfg:::fill_well_known. This should resolve your concern about the "list not being filled automatically".

@rustbot ready

[petrochenkov]

Much better!
@bors r+

[bors]

📌 Commit 29afbbd has been approved by petrochenkov

It is now in the queue for this repository.

[bors]

⌛ Testing commit 29afbbd with merge f1f8687...

[bors]

☀️ Test successful - checks-actions
Approved by: petrochenkov
Pushing f1f8687 to master...

[rust-timer]

Finished benchmarking commit (f1f8687): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.9%	[0.9%, 0.9%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Cycles

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	3.3%	[3.3%, 3.3%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 665.928s -> 666.315s (0.06%)
Artifact size: 308.12 MiB -> 308.15 MiB (0.01%)