Make slash commands more discoverable (#12480)

<img width="648" alt="image"
src="https://github.com/zed-industries/zed/assets/482957/a63df904-fbbe-4e0a-80b2-c98ebee90690">

Release Notes:

- N/A

Co-authored-by: Nathan <nathan@zed.dev>

crates/ui/src/components/keybinding.rs

@@ -77,13 +77,14 @@ impl RenderOnce for KeyBinding {
                         .join(" ")
                 )
             })
+            .gap(rems(0.125))
             .flex_none()
             .children(self.key_binding.keystrokes().iter().map(|keystroke| {
                 let key_icon = Self::icon_for_key(keystroke);
 
                 h_flex()
                     .flex_none()
-                    .p_0p5()
+                    .py_0p5()
                     .rounded_sm()
                     .text_color(cx.theme().colors().text_muted)
                     .when(keystroke.modifiers.function, |el| {