Rename indexables to indexable_uris #11788

Job	Run time
lint_node	30s
build_node (ubuntu-latest)	1m 26s
Ruby 3.1 on ubuntu-latest	15m 40s
build_node (macos-latest)	1m 55s
lint_ruby	20s
Ruby 3.2 on ubuntu-latest	17m 27s
build_node (windows-latest)	6m 22s
spelling	12s
Ruby 3.3 on ubuntu-latest	11m 59s
Verify Jekyll website builds	8s
Ruby 3.1 on macos-latest	12m 18s
Ruby 3.2 on macos-latest	10m 35s
Ruby 3.3 on macos-latest	7m 19s
Ruby 3.1 on windows-latest	22m 54s
Ruby 3.2 on windows-latest	23m 15s
Ruby 3.3 on windows-latest	25m 18s
	2h 37m 38s

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