Handle a bit more when simulating input

This isn't great, but it adds tab/return/delete, which feels
like the bare minimum; we can implement more as future work.

druid-shell/src/text.rs

@@ -403,6 +403,7 @@ pub fn simulate_input<H: WinHandler + ?Sized>(
     event: KeyEvent,
 ) -> bool {
     if handler.key_down(event.clone()) {
+        eprintln!("key handled, returning early");
         return true;
     }
 
@@ -450,6 +451,26 @@ pub fn simulate_input<H: WinHandler + ?Sized>(
                 input_handler.handle_action(Action::Move(movement));
             }
         }
+        KbKey::Backspace => {
+            input_handler.handle_action(Action::Delete(Movement::Grapheme(Direction::Upstream)));
+        }
+        KbKey::Enter => {
+            // I'm sorry windows, you'll get IME soon.
+            input_handler.handle_action(Action::InsertNewLine {
+                ignore_hotkey: false,
+                newline_type: '\n',
+            });
+        }
+        KbKey::Tab => {
+            let action = if event.mods.shift() {
+                Action::InsertBacktab
+            } else {
+                Action::InsertTab {
+                    ignore_hotkey: false,
+                }
+            };
+            input_handler.handle_action(action);
+        }
         _ => {
             handler.release_input_lock(token);
             return false;