Add sql-lint as linter

[joereynolds]

Hey,
This adds support for the sql-linter sql-lint.

There was a previous pr however I'm closing it as the branch had gone away as I did some cleaning of my laptop/github.

I've addressed the comments that were posted on there.

• Tests have been added
• The linter is no longer MySQL specific so the other comment about detecting if it's MySQL only is no longer valid

Thanks!

[joereynolds]

Hey @w0rp I saw your comment on Reddit about pinging for your attention so I'm doing that (though I do feel cheeky).

Hope the PR is okay!

[joereynolds]

Hey, is there an update on this? I've been working off my own fork of Ale because this is still yet to be merged in.
Thanks!

[reelbeelveel]

Any update? I would like to use this feature as well.

[stale]

This pull request has been automatically marked as stale because it has not been updated recently. Make sure to write tests and document your changes. See :help ale-dev for information on writing tests.
If your pull request is good to merge, bother w0rp or another maintainer again, and get them to merge it.

[joereynolds]

This is not stale, these changes still apply, pinging @w0rp

[w0rp]

We need to add this to the supported tools, but I'll add it.

[w0rp]

Cheers! 🍻