Advance RFC #1029 `"Deprecate app-prefix, app-suffix, tests-prefix, and tests-suffix"` to Stage Ready for Release #1397

Job	Run time
Does PR add RFCs?	4s
Only one RFC can be added in a PR	0s
Stage must be 'Exploring' (via label) for new RFC before merging	0s
RFC must be in only one stage before merging (labels)	0s
Frontmatter stage must be 'accepted' before merging	0s
Verify Accepted PR URL is correct	0s
Filename matches RFC number	0s
	4s

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