Add exact matching option to keymap editor search (#34497)

We know have the ability to filter matches in the keymap editor search
by exact keystroke matches. This allows user's to have the same behavior
as vscode when they toggle all actions with the same bindings

We also fixed a bug where conflicts weren't counted correctly when
saving a keymapping. This cause issues where warnings wouldn't appear
when they were supposed to.

Release Notes:

- N/A

---------

Co-authored-by: Ben Kunkle <ben@zed.dev>

crates/icons/src/icons.rs

@@ -107,6 +107,7 @@ pub enum IconName {
     Ellipsis,
     EllipsisVertical,
     Envelope,
+    Equal,
     Eraser,
     Escape,
     Exit,