Inconsistencies in short helps (`-h`) use of long help

[epage]

From #5491

location	short	long	notes
before help	before_help	before_long_help or before_help	added in #2008, changed in #2174
command about	about	long_about or about	changed in #1612
arg help	help or long_help	long_help or help
subcommand about	about or long_about	about or long_about	changed in #2558
after help	after_help	after_long_help or after_help	added in #2008, changed in #2174

The inconsistency in "command about"'s short and "subcommand about" is suspicious

Likely the fallback to long help isn't worth it and dropping it could reduce some overhead. We'd still need the long help to short help fallback.