Revert to the use of `do_add_alert_words()` in `add_alert_words()`
instead of `do_set_alert_words()` since it is used for serving a
PUT request. This change seems to be mistakenly done in commit
`d564a76f8e45b24cd2c66475ef7693582fb2f5fc'.
For a long time, rest_dispatch has had this hack where we have to
create a copy of it in each views file using it, in order to directly
access the globals list in that file. This removes that hack, instead
making rest_dispatch just use Django's import_string to access the
target method to use.
[tweaked and reorganized from acrefoot's original branch in various
ways by tabbott]