Reduce display_map snapshot creation (#39354)

Re-applies https://github.com/zed-industries/zed/pull/30840

This PR re-applies the initial
[PR](https://github.com/zed-industries/zed/pull/30840). As it was closed
because it was hard to land, because of the many conflicts. This PR
re-applies the changes for it.

In several cases we were creating multiple display_map
snapshots within the same root-level function call.
Creating a display_map snapshot is quite slow, and in some
cases we were creating the snapshot multiple times.

Release Notes:

- N/A

crates/vim/src/insert.rs

@@ -84,7 +84,7 @@ impl Vim {
         self.update_editor(cx, |_, editor, cx| {
             let snapshot = editor.buffer().read(cx).snapshot(cx);
             let mut edits = Vec::new();
-            for selection in editor.selections.all::<Point>(cx) {
+            for selection in editor.selections.all::<Point>(&editor.display_snapshot(cx)) {
                 let point = selection.head();
                 let new_row = match direction {
                     Direction::Next => point.row + 1,