vim: subword motions (#8725)

Add subword motions to vim, inspired by
[nvim-spider](https://github.com/chrisgrieser/nvim-spider),
[CamelCaseMotion](https://github.com/bkad/CamelCaseMotion).


Release Notes:

- Added subword motions to vim

crates/vim/src/test/vim_test_context.rs

@@ -159,6 +159,19 @@ impl VimTestContext {
         assert_eq!(self.mode(), mode_after, "{}", self.assertion_context());
         assert_eq!(self.active_operator(), None, "{}", self.assertion_context());
     }
+
+    pub fn assert_binding_normal<const COUNT: usize>(
+        &mut self,
+        keystrokes: [&str; COUNT],
+        initial_state: &str,
+        state_after: &str,
+    ) {
+        self.set_state(initial_state, Mode::Normal);
+        self.cx.simulate_keystrokes(keystrokes);
+        self.cx.assert_editor_state(state_after);
+        assert_eq!(self.mode(), Mode::Normal, "{}", self.assertion_context());
+        assert_eq!(self.active_operator(), None, "{}", self.assertion_context());
+    }
 }
 
 impl Deref for VimTestContext {