Add decorator for udwf

[timsaucer]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

This is a follow on to #1040 which added decorators for udf and udaf. We should give the same treatment to udwf.

Describe the solution you'd like

Implement udwf decorators, but probably not until #1055 lands on main which changes the decorator code around.

Describe alternatives you've considered

None

[kosiew]

take