fix(menu): styling

Also improves the styling of resize indicators, and removes the unnecessary `.density()` method call for the SSD header.

src/shell/element/stack/tab.rs

@@ -158,7 +158,7 @@ impl<Message: TabMessage + 'static> Tab<Message> {
             id,
             app_icon: from_name(app_id.into()).size(16).icon(),
             title: title.into(),
-            font: cosmic::font::FONT,
+            font: cosmic::font::default(),
             close_message: None,
             press_message: None,
             right_click_message: None,

src/shell/element/stack/tab_text.rs

@@ -39,7 +39,7 @@ impl TabText {
         TabText {
             width: Length::Shrink,
             height: Length::Shrink,
-            font: cosmic::font::DEFAULT,
+            font: cosmic::font::default(),
             font_size: 14.0,
             selected,
             text,

src/shell/element/stack/tabs.rs

@@ -134,7 +134,7 @@ where
                     } else {
                         TabBackgroundTheme::ActiveDeactivated
                     })
-                    .font(cosmic::font::FONT_SEMIBOLD)
+                    .font(cosmic::font::semibold())
                     .active()
             } else if i.checked_sub(1) == Some(active) {
                 tab.rule_style(rule).non_active()