protocol: rename send methods to get grouping by prefix

protocol: shuffle server methods to group send methods

protocol: do not translate error messages on the remote side

protocol: use return shortcut instead of respond function

protocol: command must be checked before passing in

tests: rename some tests to help grouping

keyword: add extra datefilters in a single update call

Merge with stable

Merge with main

cmdutil: fix accidental name clash with revrange function The revrange function was used further up, and when a local variable is defined with the same name, the earlier call to revrange becomes a 'local variable used before assignment' error. The clash was introduced in 890ad9d6a169.