* InputHelper returns full words, not just suffixes. I liked the fact that
suffixes made it impossible to violate the "all matches will start with
your prefix" invariant, but in practice it was fiddly to work with.
* add ih.when_wordlist_is_available(), so the frontend can block (after
claiming the nameplate) until it can return a complete wordlist to
readline. This helps the user experience, because readline wasn't really
built to work with completions that change over time
* make the Wordlist responsible for appending hyphens to all non-final word
completions. InputHelper remains responsible for hyphens on nameplates.
This makes the frontend simpler, but I may change it again in the future if
it helps non-readline GUI frontends.
* CodeInputter: after claiming, wait for the wordlist rather than returning
an empty list
* PGPWordList: change to match
This has the unfortunate side-effect that e.g. typing "3-yucatan-tu TAB"
shows you completions that include the entire phrase: "3-yucatan-tumor
3-yucatan-tunnel", rather than only mentioning the final word. I'd like to
fix this eventually.
