Improve guidance from snippet-bot

[grayside]

Problem

snippet-bot provides guidance on the sample impact of pull requests.

However, this guidance provides a basic level of reporting that presumes deep subject-matter knowledge by the reader.

Screenshot showing snippet-bot message

Samples contributors less familiar with these details will either ignore this, or self-block until more details are available.

Proposal

• Do not report moved region tags as sample browser page deletion
• Clarify not just removing region tag, but removing region tag from known path is the problem
• Clarify that moving region tag should be paused on docs coordination