feat: generic linter, absorbing cdot linter and attribute [instance] in linter

[adomani]

A "generic" syntax linter that can be configured using a function Syntax → Array Syntax.
The expectations is that the function returns sub-syntax extracted from the input that should be flagged by the linter.

This PR provides two examples.

• Flags uses of cdot that are not typed as ·.
  • [Merged by Bors] - chore: substitute some . with · #12137
    is a PR that inspired this one.
• Flag uses of attribute [instance] in that is not limited to the next declaration
  • Inspired by the existing PR by Michael Rothgang
    [Merged by Bors] - feat: lint attribute [instance] instName in #13190

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[adomani]

!bench

[leanprover-bot]

Here are the benchmark results for commit b9ee1c4.
There were no significant changes against commit 7c5b29b.

[grunweg]

awaiting-author

[adomani]

Michael, thanks for reviewing!

I had intended this PR as an experiment for the "generic" framework and I thought that cdot was a good candidate, since it is just a style lint, rather than something more substantial.

However, as a further experiment, you can see how now the linter is flexible enough to lint against both cdots and your "attribute_instance_in" uniformly.

[grunweg]

🎉 Wow, thanks for rewriting my linter!
I wasn't sure whether an attribute declaration was always at the top (as opposed to possibly being nested): it seems it always is, so your simplification works. And I like your test file - it's both slightly more comprehensive and requires fewer imports than what I cobbled together.

I see some tension between code duplication and error messages: having all errors be about linter.generic is a strictly worse user experience; deduplicating the same boilerplate is also annoying.

[adomani]

Maybe we could have something like set_option no_lint "cdot" to selectively disable cdot. I think that Strings can be supported.

The implementation of the linter would need to handle these refined options.

Also, we may have to disengage from logLint.

[github-actions]

PR summary bb394346c8

Import changes for modified files

No significant changes to the import graph

Import changes for all files

Files	Import difference
There are 4003 files with changed transitive imports: this is too many to display!

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Declarations diff

+ findDot
+ genericSyntaxLinter
+ getLinterHash
+ instance : Inhabited Nat
+ isCDot?
+ is_attribute_instance_in
+ unwanted.cDot
+++++++++++++ instance : Inhabited Int

You can run this locally as follows

## summary with just the declaration names:
./scripts/declarations_diff.sh <optional_commit>

## more verbose report:
./scripts/declarations_diff.sh long <optional_commit>