vim: f and t multiline option (#8448)

I'm not sure how compliant you're aiming to be with vim, but the `f`
behavior is more useful when it can search on multiple lines instead of
a single one, so I'd like to propose this change.

This change is quite frequent in vim/neovim as a plugin (e.g.
[clever-f](https://github.com/VSCodeVim/Vim),
[improved-ft](https://github.com/backdround/improved-ft.nvim), etc), and
in other vim emulations (e.g.
[vscode-vim](https://github.com/VSCodeVim/Vim)).

crates/editor/src/movement.rs

@@ -12,7 +12,7 @@ use std::{ops::Range, sync::Arc};
 /// Defines search strategy for items in `movement` module.
 /// `FindRange::SingeLine` only looks for a match on a single line at a time, whereas
 /// `FindRange::MultiLine` keeps going until the end of a string.
-#[derive(Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum FindRange {
     SingleLine,
     MultiLine,