Set some much needed properties on PidginConversation

This sets a bunch of properties on the Input widget in PidginConversation.

* wrap-mode is set to word-char as it should have been.
* input mode is set to free form.
* input hints turns on spellchecking, emoji, and word-completion.

Testing Done:
Joined an IRC channel and typed some really long lines.

Reviewed at https://reviews.imfreedom.org/r/2796/