Removals: Link to deprecation issue, make formatting consistent

What does this MR do?

Essentially it does the same thing as !120200 (merged), but for removals instead of deprecations.

This MR also adopts the newer, less ⚠ RED AND ANGRY style of noting which changes are breaking changes.

Quoting from that MR:

Deprecation issues are required, as stated in the YAML template, MR template, and the handbook. But, deprecation notices don't automatically link to those issues. So, you have to reference the deprecation issue in the text of your notice if you want to direct users to the issue.

This MR:

• Adds a link to the deprecation issue, if it's provided.
• Adjusts the wording of the breaking-change notice to avoid confusion as reported in gitlab-com/Product#5558 (comment 1372612533).

Suggestion: Let's not merge this until all the pending removal MRs are merged. If we merge it earlier, we'll force everyone with removals still pending to re-run the rake task. I think we could:

1. Allow pending removal MRs to merge by the 17th.
2. Re-run the rake task and merge this MR on the 18th.

Related issues

gitlab-com/Product#5558 (comment 1384202041)

Screenshots

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