vim: Add motion support for toggle comments (#14919)

### Summary

This PR adds support for count and object motions to the toggle comments
action in Vim mode. The relevant issue is
[#14337](https://github.com/zed-industries/zed/issues/14337).

For example, `2 g c j` will toggle comments three lines downward. `g c g
g` will toggle comments from the current cursor position up to the start
of the file.

Notably missing from this PR are `g c b` (toggle comments for the
current block) as well as `g c p` (toggle comments for the current
paragraph). These seem to be non-standard.

The new module `normal/toggle_comments.rs` has been copied almost
verbatim from `normal/indent.rs`. Maybe that ought to be abstracted over
but I feel I lack the overview.

Release Notes:

- vim: Added support for count and object motion to the toggle comments
action ([#14337](https://github.com/zed-industries/zed/issues/14337)).

crates/vim/src/normal.rs

@@ -9,6 +9,7 @@ pub(crate) mod repeat;
 mod scroll;
 pub(crate) mod search;
 pub mod substitute;
+mod toggle_comments;
 pub(crate) mod yank;
 
 use std::collections::HashMap;
@@ -39,6 +40,7 @@ use self::{
     change::{change_motion, change_object},
     delete::{delete_motion, delete_object},
     indent::{indent_motion, indent_object, IndentDirection},
+    toggle_comments::{toggle_comments_motion, toggle_comments_object},
     yank::{yank_motion, yank_object},
 };
 
@@ -237,6 +239,7 @@ pub fn normal_motion(
             Some(Operator::OppositeCase) => {
                 change_case_motion(vim, motion, times, CaseTarget::OppositeCase, cx)
             }
+            Some(Operator::ToggleComments) => toggle_comments_motion(vim, motion, times, cx),
             Some(operator) => {
                 // Can't do anything for text objects, Ignoring
                 error!("Unexpected normal mode motion operator: {:?}", operator)
@@ -273,6 +276,7 @@ pub fn normal_object(object: Object, cx: &mut WindowContext) {
                         target: Some(SurroundsType::Object(object)),
                     });
                 }
+                Some(Operator::ToggleComments) => toggle_comments_object(vim, object, around, cx),
                 _ => {
                     // Can't do anything for namespace operators. Ignoring
                 }