checks: fix some yamllint and markdownlint errors

[nilason]

Fixes some pre-commit yamllint and markdownlint errors, which have sneaked in again.

[echoix]

I find the indentation weird on the labeler file. It seems a bit more than expected.

Would you think it would be better to match it with upgrading the tool version in the pre commit config? I remember that at least one of them was broken and would never work. #3318 Ah, it was flake8.

If there was a config file, .yamllint.yml, we could have the same config in precommit, other ide intregrations, but more specifically, the super-linter could be configured to have the same settings, and enforce it there.

The default config file used in Megalinter is the minimum required so that yamllint and prettier don't conflict each other https://github.com/oxsecurity/megalinter/blob/03986e6993ccf699a22451118520680b438e7d2a/TEMPLATES/.yamllint.yml
Super-linter's default config file is https://github.com/super-linter/super-linter/blob/53361158a1cdd3b7660986e00d8635147970e842/TEMPLATES/.yaml-lint.yml

The current config used for pre-commit is

grass/.pre-commit-config.yaml

Lines 69 to 76 in f8115df

	- repo: https://github.com/adrienverge/yamllint.git
	rev: v1.29.0
	hooks:
	- id: yamllint
	args: [--format, parsable, --strict, -d,
	'{extends: default, rules: {truthy: disable,
	line-length: {max: 120, allow-non-breakable-words: true},
	comments: {min-spaces-from-content: 1}}}']

Also, maybe a basic .editorconfig could be helpful for setting some of the formatting that we use.

[echoix]

There's nothing wrong with these changes, so I'm not blocking it for weeks, but as my comment, I think having a solution that prevents this from happening would be even better.