Add commands to select next/previous siblings in the syntax tree (#35053)

Closes #5133 and discussion
https://github.com/zed-industries/zed/discussions/33493

This PR adds two new commands to select next/previous siblings in the
syntax tree. These commands were modelled after the existing ones about
expand/shrink selection. With this PR I've added new key bindings
inspired by `helix` for previous / next / expand / shrink selections.



https://github.com/user-attachments/assets/4ef7fadb-0b82-4897-95c7-1737827bf4ac


Release Notes:

- Add commands to select next/previous siblings in the syntax tree

---------

Co-authored-by: Joseph T. Lyons <JosephTLyons@gmail.com>

crates/vim/src/visual.rs

@@ -53,6 +53,10 @@ actions!(
         SelectSmallerSyntaxNode,
         /// Selects the next larger syntax node.
         SelectLargerSyntaxNode,
+        /// Selects the next syntax node sibling.
+        SelectNextSyntaxNode,
+        /// Selects the previous syntax node sibling.
+        SelectPreviousSyntaxNode,
         /// Restores the previous visual selection.
         RestoreVisualSelection,
         /// Inserts at the end of each line in visual selection.
@@ -110,6 +114,30 @@ pub fn register(editor: &mut Editor, cx: &mut Context<Vim>) {
         }
     });
 
+    Vim::action(editor, cx, |vim, _: &SelectNextSyntaxNode, window, cx| {
+        let count = Vim::take_count(cx).unwrap_or(1);
+        Vim::take_forced_motion(cx);
+        for _ in 0..count {
+            vim.update_editor(cx, |_, editor, cx| {
+                editor.select_next_syntax_node(&Default::default(), window, cx);
+            });
+        }
+    });
+
+    Vim::action(
+        editor,
+        cx,
+        |vim, _: &SelectPreviousSyntaxNode, window, cx| {
+            let count = Vim::take_count(cx).unwrap_or(1);
+            Vim::take_forced_motion(cx);
+            for _ in 0..count {
+                vim.update_editor(cx, |_, editor, cx| {
+                    editor.select_prev_syntax_node(&Default::default(), window, cx);
+                });
+            }
+        },
+    );
+
     Vim::action(
         editor,
         cx,
@@ -1839,4 +1867,37 @@ mod test {
             fˇ»ox"
         });
     }
+
+    #[gpui::test]
+    async fn test_visual_syntax_sibling_selection(cx: &mut gpui::TestAppContext) {
+        let mut cx = VimTestContext::new(cx, true).await;
+
+        cx.set_state(
+            indoc! {"
+                fn test() {
+                    let ˇa = 1;
+                    let b = 2;
+                    let c = 3;
+                }
+            "},
+            Mode::Normal,
+        );
+
+        // Enter visual mode and select the statement
+        cx.simulate_keystrokes("v w w w");
+        cx.assert_state(
+            indoc! {"
+                fn test() {
+                    let «a = 1;ˇ»
+                    let b = 2;
+                    let c = 3;
+                }
+            "},
+            Mode::Visual,
+        );
+
+        // The specific behavior of syntax sibling selection in vim mode
+        // would depend on the key bindings configured, but the actions
+        // are now available for use
+    }
 }