docs(eslint-plugin): add docs for signal-store-feature-should-use-generic-type

[timdeschryver]

…eric-type

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• Tests for the changes have been added (for bug fixes / features)
• Documentation has been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
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What is the current behavior?

Closes #4502

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

This PR continues the work from #4515, which was disbanded.

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[timdeschryver]

As mentioned in the referenced PR, this is removed to keep things consistent across the different rules.