[FEATURE ember-views-text-support-on-change]

Fixes #5492.

When an `<input type="text">` or `<textarea>` value changes, expose and emit a
`change` event.
@trek is this the type of documentation you were talking about?

I ask because I didn't add the method itself, only the guarded `sendAction` call. I have a hunch that this method was deliberately undocumented.