docs: correct return type for `around_action` #3753

Job	Run time
ash-ci (Picosat) / mix deps.get	13s
ash-ci (SimpleSat) / mix deps.get	14s
ash-ci (Picosat) / MIX_ENV=dev mix.compile	52s
ash-ci (Picosat) / MIX_ENV=test mix.compile	55s
ash-ci (Picosat) / audit	1m 9s
ash-ci (SimpleSat) / audit	1m 17s
ash-ci (SimpleSat) / MIX_ENV=test mix.compile	1m 4s
ash-ci (SimpleSat) / MIX_ENV=dev mix.compile	42s
ash-ci (SimpleSat) / mix docs	1m 4s
ash-ci (Picosat) / mix docs	55s
ash-ci (Picosat) / mix credo --strict	1m 0s
ash-ci (Picosat) / mix dialyzer	4m 7s
ash-ci (Picosat) / mix format --check-formatted	51s
ash-ci (Picosat) / mix ash.codegen --check	0s
ash-ci (Picosat) / mix sobelow	1m 4s
ash-ci (Picosat) / mix spark.cheat_sheets --check	49s
ash-ci (Picosat) / mix spark.formatter --check	59s
ash-ci (Picosat) / mix test	2m 22s
ash-ci (Picosat) / mix deps.unlock --check-unused	59s
ash-ci (SimpleSat) / mix format --check-formatted	1m 1s
ash-ci (SimpleSat) / mix dialyzer	4m 8s
ash-ci (SimpleSat) / mix credo --strict	1m 0s
ash-ci (SimpleSat) / mix ash.codegen --check	0s
ash-ci (SimpleSat) / mix sobelow	59s
ash-ci (SimpleSat) / mix spark.cheat_sheets --check	1m 1s
ash-ci (SimpleSat) / mix spark.formatter --check	48s
ash-ci (SimpleSat) / mix test	2m 44s
ash-ci (SimpleSat) / mix deps.unlock --check-unused	52s
ash-ci (Picosat) / Deploy docs to GitHub pages.	0s
ash-ci (SimpleSat) / Deploy docs to GitHub pages.	0s
ash-ci (Picosat) / Release	0s
ash-ci (SimpleSat) / Release	0s
	33m 9s

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