Use alt modifier instead of cmd to add selections

crates/gpui/src/app.rs

@@ -3650,6 +3650,8 @@ mod tests {
         presenter.borrow_mut().dispatch_event(
             Event::LeftMouseDown {
                 position: Default::default(),
+                ctrl: false,
+                alt: false,
                 shift: false,
                 cmd: false,
                 click_count: 1,

crates/gpui/src/platform/event.rs

@@ -14,8 +14,10 @@ pub enum Event {
     },
     LeftMouseDown {
         position: Vector2F,
-        cmd: bool,
+        ctrl: bool,
+        alt: bool,
         shift: bool,
+        cmd: bool,
         click_count: usize,
     },
     LeftMouseUp {

crates/gpui/src/platform/mac/event.rs

@@ -92,6 +92,8 @@ impl Event {
                         native_event.locationInWindow().x as f32,
                         window_height - native_event.locationInWindow().y as f32,
                     ),
+                    ctrl: modifiers.contains(NSEventModifierFlags::NSControlKeyMask),
+                    alt: modifiers.contains(NSEventModifierFlags::NSAlternateKeyMask),
                     shift: modifiers.contains(NSEventModifierFlags::NSShiftKeyMask),
                     cmd: modifiers.contains(NSEventModifierFlags::NSCommandKeyMask),
                     click_count: native_event.clickCount() as usize,