ui: Make Label respect the ui_font_weight setting (#15241)

This PR makes the `Label` component respect the `ui_font_weight`
setting, by default.

An explicit font weight can still be set via the `weight` method, which
will override the `ui_font_weight` for that `Label`.

<img width="1566" alt="Screenshot 2024-07-25 at 8 55 16 PM"
src="https://github.com/user-attachments/assets/2751e29c-c76e-4685-8564-604b3b77f603">

Release Notes:

- Updated UI labels to respect the `ui_font_weight` setting
([#15234](https://github.com/zed-industries/zed/issues/15234)).

crates/ui/src/styles/typography.rs

@@ -102,7 +102,7 @@ pub enum TextSize {
     XSmall,
 
     /// The `ui_font_size` set by the user.
-    UI,
+    Ui,
     /// The `buffer_font_size` set by the user.
     Editor,
     // TODO: The terminal settings will need to be passed to
@@ -120,7 +120,7 @@ impl TextSize {
             Self::Default => rems_from_px(14.),
             Self::Small => rems_from_px(12.),
             Self::XSmall => rems_from_px(10.),
-            Self::UI => rems_from_px(theme_settings.ui_font_size.into()),
+            Self::Ui => rems_from_px(theme_settings.ui_font_size.into()),
             Self::Editor => rems_from_px(theme_settings.buffer_font_size.into()),
         }
     }