Define a proper completion function

inf-ruby-mode: Add to completion-at-point-functions.

inf-ruby-completion-at-point: Adhere to that interface.

inf-ruby-completion-bounds-of-expr-at-point: Return nil when inside a word.

inf-ruby-complete, inf-ruby-complete-replace-expr, inf-ruby-complete-or-tab: Remove.

Bump the version

Version 2.2.4

Version 2.2.3

Version 2.2

Initial revision.