Simplify input capture

Instead of "injecting" characters into the input stream, the input
stream is now forwarded to the `musicplayer`. It has will have to
decide what to do with the stream, e.g. by setting the "mode" to
something that captures the input stream and acts upon it

src/musicplayer.gleam

@@ -8,15 +8,13 @@ import musicplayer/ui/ui
 
 pub fn main() -> Nil {
   let input_keys_name: Name(Key) = process.new_name("input_keys")
-  let input_inject_name: Name(Key) = process.new_name("input_inject_keys")
 
-  input.new(input_keys_name, input_inject_name)
+  input.new(input_keys_name)
 
   let assert Ok(ui) = ui.new()
   let assert Ok(mpv) = mpv.new()
 
   let exit = process.new_subject()
-  let assert Ok(_) =
-    musicplayer.new(ui, mpv, input_keys_name, input_inject_name, exit)
+  let assert Ok(_) = musicplayer.new(ui, mpv, input_keys_name, exit)
   process.receive_forever(exit)
 }