Expand on the actor docstring for the el8->el9 rubygem-irb symlink fix. #4198

Job	Run time
Run unit tests in containers (Run unit tests for el9toel10 and common repositories on python 3.12...	52s
Run unit tests in containers (Run python linters for el9toel10 and common repositories on python ...	1m 23s
Run unit tests in containers (Run unit tests for el9toel10 and common repositories on python 3.9,...	55s
Run unit tests in containers (Run python linters for el9toel10 and common repositories on python ...	1m 21s
Run unit tests in containers (Run unit tests for el8toel9 and common repositories on python 3.9, ...	59s
Run unit tests in containers (Run python linters for el8toel9 and common repositories on python 3...	1m 36s
Run unit tests in containers (Run unit tests for el8toel9 and common repositories on python 3.6, ...	1m 16s
Run unit tests in containers (Run python linters for el8toel9 and common repositories on python 3...	3m 37s
Run unit tests in containers (Run unit tests for el7toel8 and common repositories on python 3.6, ...	1m 15s
Run unit tests in containers (Run python linters for el7toel8 and common repositories on python 3...	4m 18s
Run unit tests in containers (Run unit tests for el7toel8 and common repositories on python 2.7, ...	1m 33s
Run unit tests in containers (Run python linters for el7toel8 and common repositories on python 2...	7m 14s
	26m 19s

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