Flesh out helix bindings (#28103)

This brings in a bunch of helix bindings (many of them from
infogulch/zed-helix-keymap) and implements helix-style delete.

Release Notes:

- vim: Expanded default helix-style keybindings in HelixNormal mode

crates/vim/src/normal.rs

@@ -48,6 +48,7 @@ actions!(
         JoinLinesNoWhitespace,
         DeleteLeft,
         DeleteRight,
+        HelixDelete,
         ChangeToEndOfLine,
         DeleteToEndOfLine,
         Yank,
@@ -92,6 +93,21 @@ pub(crate) fn register(editor: &mut Editor, cx: &mut Context<Vim>) {
         let times = Vim::take_count(cx);
         vim.delete_motion(Motion::Right, times, window, cx);
     });
+
+    Vim::action(editor, cx, |vim, _: &HelixDelete, window, cx| {
+        vim.record_current_action(cx);
+        vim.update_editor(window, cx, |_, editor, window, cx| {
+            editor.change_selections(None, window, cx, |s| {
+                s.move_with(|map, selection| {
+                    if selection.is_empty() {
+                        selection.end = movement::right(map, selection.end)
+                    }
+                })
+            })
+        });
+        vim.visual_delete(false, window, cx);
+    });
+
     Vim::action(editor, cx, |vim, _: &ChangeToEndOfLine, window, cx| {
         vim.start_recording(cx);
         let times = Vim::take_count(cx);

crates/vim/src/vim.rs

@@ -438,7 +438,7 @@ impl Vim {
 
         vim.update(cx, |_, cx| {
             Vim::action(editor, cx, |vim, _: &SwitchToNormalMode, window, cx| {
-                vim.switch_mode(Mode::Normal, false, window, cx)
+                vim.switch_mode(vim.default_mode(cx), false, window, cx)
             });
 
             Vim::action(editor, cx, |vim, _: &SwitchToInsertMode, window, cx| {
@@ -739,6 +739,10 @@ impl Vim {
         cx.on_release(|_, _| drop(subscription)).detach();
     }
 
+    pub fn default_mode(&self, cx: &App) -> Mode {
+        VimSettings::get_global(cx).default_mode
+    }
+
     pub fn editor(&self) -> Option<Entity<Editor>> {
         self.editor.upgrade()
     }
@@ -1105,7 +1109,7 @@ impl Vim {
             }
         }
 
-        if mode == "normal" || mode == "visual" || mode == "operator" {
+        if mode == "normal" || mode == "visual" || mode == "operator" || mode == "helix_normal" {
             context.add("VimControl");
         }
         context.set("vim_mode", mode);