Fix docs linting issues

[gsteel]

Q	A
Documentation	yes
QA	yes

[gsteel]

@froschdesign Can you advise what to do about /docs/index.md - can it be deleted?

[froschdesign]

@gsteel

…can it be deleted?

Unfortunately not, because MkDocs produce an error if the file is listed in the navigation but not in the file system. And the navigation entry is needed, otherwise the homepage is missing.

[froschdesign]

And here we have special case because the content of index.md is used for the homepage instead of auto-generated:

laminas-cache/docs/book/index.md

Lines 9 to 15 in f25e67a

	## Learn
	<ul class="list-group list-group-flush">
	<li class="list-group-item">
	<a href="/laminas-cache/v3/application-integration/usage-in-a-laminas-mvc-application/">Usage in a laminas-mvc application</a>
	</li>
	</ul>

https://docs.laminas.dev/laminas-cache/#learn

[gsteel]

I've just disabled linting for index.md - that OK?