Partially add zwp-input-method-v2

[dcz-self]

Only the input-method object is supported. No keyboard grab, no popup surface.

This is already useful.

Client demo: https://codeberg.org/dcz/stiwri

The client only does a couple canned requests, but it shows:

• looking at preedit (command line)
• submitting text (button)
• showing preedit (buttons)

which is most of the functionality here.

[PolyMeilex]

I'm no IME expert, but this looks good to me so far.

[dcz-self]

Thanks a lot for the review!

While working on supporting the next input-method, I noticed that I missed the connection: &Connection param in Handler. It's added now.

[PolyMeilex]

Thanks for working on this, excited to see where the whole IME Wayland story will go

[PolyMeilex]

I noticed that I missed the connection: &Connection param in Handler

btw, it's not strictly required, as Connection is Clone. So one could just store it in the state.

[dcz-self]

I still use the Connection in the app state, but I added it for consistency... and for when someone decides to use 2 connections I guess :P

[dcz-self]

Thanks for reviewing!