CLEANUP: anon: clarify the help message on "debug dev hash"

CLEANUP: anon: clarify the help message on "debug dev hash"

This command is used to hash a section name using the current anon key,
it was brought in 2.7 by commit 54966dffd ("MINOR: anon: store the
anonymizing key in the CLI's appctx"). However the help message only
says "return msg hashed" which is misleading because if anon mode is
not enabled, it returns the string as-is. Let's just mention this
condition in the help message, and also fix the alphabetical ordering
and alignment on the line.