Add missing fullstop in stale error #7516

Job	Run time
Get the latest prelude hash	3s
build (ubuntu-22.04, aarch64-unknown-linux-gnu, true)	11m 0s
build (ubuntu-22.04, aarch64-unknown-linux-musl, true)	11m 5s
build (ubuntu-22.04, x86_64-unknown-linux-gnu)	10m 7s
build (ubuntu-22.04, x86_64-unknown-linux-musl, true)	10m 36s
build (macos-13, aarch64-apple-darwin, true)	17m 33s
build (macos-13, x86_64-apple-darwin)	15m 19s
build (windows-2022, x86_64-pc-windows-msvc, true)	18m 33s
Publish buck2.build	2m 22s
Release `latest` tag	41s
Check if there's a release for this half of the month already	5s
Release bi-monthly tag	0s
	1h 37m 24s

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