vim: Add more diff stuff (#17456)

Release Notes:

- vim: Added `:diff` and `:revert` (that work with `'<,'>`) to open the
selected diff and revert it.
- vim: Added `d o` to open the diff and `d p` to revert (spiritually
similar to vim's do/dp, though obviously not the same)
- vim: Added `ctrl-p` and `ctrl-n` to summon the autocomplete menu in
insert mode.

crates/vim/src/command.rs

@@ -586,6 +586,8 @@ fn generate_commands(_: &AppContext) -> Vec<VimCommand> {
         VimCommand::new(("lp", "revious"), editor::actions::GoToPrevDiagnostic).count(),
         VimCommand::new(("lN", "ext"), editor::actions::GoToPrevDiagnostic).count(),
         VimCommand::new(("j", "oin"), JoinLines).range(),
+        VimCommand::new(("dif", "fupdate"), editor::actions::ToggleHunkDiff).range(),
+        VimCommand::new(("rev", "ert"), editor::actions::RevertSelectedHunks).range(),
         VimCommand::new(("d", "elete"), VisualDeleteLine).range(),
         VimCommand::new(("y", "ank"), VisualYankLine).range(),
         VimCommand::new(("sor", "t"), SortLinesCaseSensitive).range(),