#502 mh-complete-word is unused

[Mike Kupfer]

In Emacs master (7dab52dfbc), mh-complete-word is defined but not used by MH-E. It used to be used by mh-letter-complete, but that got ripped out in f8d750135e9. So mh-complete-word could probably go away, too, though we might want to query mh-users first, and maybe we should first mark it obsolete.

[Bill Wohler]

I'd be inclined to do the same thing as mh-letter-complete if an alternative is available. That is, to rip out the function and mark it obsolete with its replacement. For example:

+(define-obsolete-function-alias 'mh-letter-complete

+  #'completion-at-point "29.1")

Otherwise, yes, just mark it obsolete and remove it in the next major version.