Improve changelog linting

[phlax]

A couple of issues are cropping up in the changelog files

Currently it doesnt check for the text type (ie missing |) on the change strings

there is also a regression where it no longer checks for capitalization on the first word

there may be others that we want to add

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• check structure of changelogs - ie have area/change for every entry
• prevent editing of historical changelogs

[phlax]

cc @alyssawilk

[adisuissa]

Related issue: #22237

[github-actions]

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