Improve check-cfg diagnostics

[Urgau]

This PR tries to improve some of the diagnostics of check-cfg.

The main changes is the unexpected name or value being added to the main diagnostic:

- warning: unexpected `cfg` condition name
+ warning: unexpected `cfg` condition name: `widnows`

It also cherry-pick the better sensible logic for when we print the list of expected values when we have a matching value for a very similar name.

Address #111072 (comment)

r? @petrochenkov

[Urgau]

Addressed the review comments, ready for another round of review.

@rustbot ready

[petrochenkov]

@bors r+

[bors]

📌 Commit ed922d8 has been approved by petrochenkov

It is now in the queue for this repository.

[bors]

⌛ Testing commit ed922d8 with merge a4a10bd...

[bors]

☀️ Test successful - checks-actions
Approved by: petrochenkov
Pushing a4a10bd to master...

[rust-timer]

Finished benchmarking commit (a4a10bd): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.5%	[-0.5%, -0.5%]	1
All ❌✅ (primary)	-	-	0

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
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.6%	[-4.2%, -3.1%]	2
All ❌✅ (primary)	-	-	0

Cycles

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

Binary size

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

Bootstrap: 627.545s -> 628.293s (0.12%)
Artifact size: 271.33 MiB -> 271.30 MiB (-0.01%)