linux: Fix IBus in vim mode and some compose state fixes (#12299)

Release Notes:

- N/A

Fixes #12198 and some minor fixes:
* IBus was intercepting normal keys like `a`, `k` which caused some
problems in vim mode.
* Wayland: Trying to commit the pre_edit on click wasn't working
properly, should be fixed now.
* X11: The pre_edit was supposed to be cleared when losing keyboard
focus.
* X11: We should commit the pre_edit on click.

---------

Co-authored-by: Mikayla Maki <mikayla@zed.dev>

crates/gpui/src/platform/linux/x11/window.rs

@@ -579,6 +579,28 @@ impl X11WindowStatePtr {
         }
     }
 
+    pub fn handle_ime_unmark(&self) {
+        let mut state = self.state.borrow_mut();
+        if let Some(mut input_handler) = state.input_handler.take() {
+            drop(state);
+            input_handler.unmark_text();
+            let mut state = self.state.borrow_mut();
+            state.input_handler = Some(input_handler);
+        }
+    }
+
+    pub fn handle_ime_delete(&self) {
+        let mut state = self.state.borrow_mut();
+        if let Some(mut input_handler) = state.input_handler.take() {
+            drop(state);
+            if let Some(marked) = input_handler.marked_text_range() {
+                input_handler.replace_text_in_range(Some(marked), "");
+            }
+            let mut state = self.state.borrow_mut();
+            state.input_handler = Some(input_handler);
+        }
+    }
+
     pub fn get_ime_area(&self) -> Option<Bounds<Pixels>> {
         let mut state = self.state.borrow_mut();
         let mut bounds: Option<Bounds<Pixels>> = None;