vim: Rename wrapping keybindings + document cursor wrapping (#25694)

https://github.com/zed-industries/zed/pull/25663#issuecomment-2686095807

Renamed the `vim::Backspace` and `vim::Space` actions to
`vim::WrappingLeft` and `vim::WrappingRight` respectively. The old names
are still available, but they are marked as deprecated and users are
advised to use the new names.

Also added a paragraph to the docs describing how to enable wrapping
cursor navigation.

crates/vim/src/normal/change.rs

@@ -27,7 +27,7 @@ impl Vim {
             Motion::Left
                 | Motion::Right
                 | Motion::EndOfLine { .. }
-                | Motion::Backspace
+                | Motion::WrappingLeft
                 | Motion::StartOfLine { .. }
         );
         self.update_editor(window, cx, |vim, editor, window, cx| {