Implement Indent & Outdent as operators (#12430)

Release Notes:

- Fixes [#9697](https://github.com/zed-industries/zed/issues/9697).

Implements `>` and `<` with motions and text objects.
Works with repeat action `.`

crates/vim/src/normal/indent.rs

@@ -0,0 +1,78 @@
+use crate::{motion::Motion, object::Object, Vim};
+use collections::HashMap;
+use editor::{display_map::ToDisplayPoint, Bias};
+use gpui::WindowContext;
+use language::SelectionGoal;
+
+#[derive(PartialEq, Eq)]
+pub(super) enum IndentDirection {
+    In,
+    Out,
+}
+
+pub fn indent_motion(
+    vim: &mut Vim,
+    motion: Motion,
+    times: Option<usize>,
+    dir: IndentDirection,
+    cx: &mut WindowContext,
+) {
+    vim.stop_recording();
+    vim.update_active_editor(cx, |_, editor, cx| {
+        let text_layout_details = editor.text_layout_details(cx);
+        editor.transact(cx, |editor, cx| {
+            let mut selection_starts: HashMap<_, _> = Default::default();
+            editor.change_selections(None, cx, |s| {
+                s.move_with(|map, selection| {
+                    let anchor = map.display_point_to_anchor(selection.head(), Bias::Right);
+                    selection_starts.insert(selection.id, anchor);
+                    motion.expand_selection(map, selection, times, false, &text_layout_details);
+                });
+            });
+            if dir == IndentDirection::In {
+                editor.indent(&Default::default(), cx);
+            } else {
+                editor.outdent(&Default::default(), cx);
+            }
+            editor.change_selections(None, cx, |s| {
+                s.move_with(|map, selection| {
+                    let anchor = selection_starts.remove(&selection.id).unwrap();
+                    selection.collapse_to(anchor.to_display_point(map), SelectionGoal::None);
+                });
+            });
+        });
+    });
+}
+
+pub fn indent_object(
+    vim: &mut Vim,
+    object: Object,
+    around: bool,
+    dir: IndentDirection,
+    cx: &mut WindowContext,
+) {
+    vim.stop_recording();
+    vim.update_active_editor(cx, |_, editor, cx| {
+        editor.transact(cx, |editor, cx| {
+            let mut original_positions: HashMap<_, _> = Default::default();
+            editor.change_selections(None, cx, |s| {
+                s.move_with(|map, selection| {
+                    let anchor = map.display_point_to_anchor(selection.head(), Bias::Right);
+                    original_positions.insert(selection.id, anchor);
+                    object.expand_selection(map, selection, around);
+                });
+            });
+            if dir == IndentDirection::In {
+                editor.indent(&Default::default(), cx);
+            } else {
+                editor.outdent(&Default::default(), cx);
+            }
+            editor.change_selections(None, cx, |s| {
+                s.move_with(|map, selection| {
+                    let anchor = original_positions.remove(&selection.id).unwrap();
+                    selection.collapse_to(anchor.to_display_point(map), SelectionGoal::None);
+                });
+            });
+        });
+    });
+}