Fix missing buffer font features in Blame UI, Hover Popover and Markdown Preview (#44657)

- Fix missing font features in 
  `git_ui::blame_ui::GitBlameRenderer.render_blame_entry`
- Fix missing buffer font features in
`markdown_preview::markdown_renderer`
- Update the way that the markdown style is built for hover popovers so
  that, for code blocks, the buffer font features are used.
- Introduce `gpui::Styled.font_features` to allow callers to also set
  the font's features, similar to how `gpui::Styled.font_family` already
  exists.

Relates to #44209

Release Notes:

- Fixed wrong font features in Blame UI, Hover Popover and Markdown
Preview

crates/editor/src/hover_popover.rs

@@ -623,7 +623,10 @@ pub fn hover_markdown_style(window: &Window, cx: &App) -> MarkdownStyle {
     });
     MarkdownStyle {
         base_text_style,
-        code_block: StyleRefinement::default().my(rems(1.)).font_buffer(cx),
+        code_block: StyleRefinement::default()
+            .my(rems(1.))
+            .font_buffer(cx)
+            .font_features(buffer_font_features.clone()),
         inline_code: TextStyleRefinement {
             background_color: Some(cx.theme().colors().background),
             font_family: Some(buffer_font_family),

crates/git_ui/src/blame_ui.rs

@@ -65,7 +65,7 @@ impl BlameRenderer for GitBlameRenderer {
                         .w_full()
                         .gap_2()
                         .justify_between()
-                        .font_family(style.font().family)
+                        .font(style.font())
                         .line_height(style.line_height)
                         .text_color(cx.theme().status().hint)
                         .child(

crates/gpui/src/styled.rs

@@ -1,8 +1,9 @@
 use crate::{
     self as gpui, AbsoluteLength, AlignContent, AlignItems, BorderStyle, CursorStyle,
-    DefiniteLength, Display, Fill, FlexDirection, FlexWrap, Font, FontStyle, FontWeight,
-    GridPlacement, Hsla, JustifyContent, Length, SharedString, StrikethroughStyle, StyleRefinement,
-    TextAlign, TextOverflow, TextStyleRefinement, UnderlineStyle, WhiteSpace, px, relative, rems,
+    DefiniteLength, Display, Fill, FlexDirection, FlexWrap, Font, FontFeatures, FontStyle,
+    FontWeight, GridPlacement, Hsla, JustifyContent, Length, SharedString, StrikethroughStyle,
+    StyleRefinement, TextAlign, TextOverflow, TextStyleRefinement, UnderlineStyle, WhiteSpace, px,
+    relative, rems,
 };
 pub use gpui_macros::{
     border_style_methods, box_shadow_style_methods, cursor_style_methods, margin_style_methods,
@@ -630,6 +631,14 @@ pub trait Styled: Sized {
         self
     }
 
+    /// Sets the font features of this element and its children.
+    fn font_features(mut self, features: FontFeatures) -> Self {
+        self.text_style()
+            .get_or_insert_with(Default::default)
+            .font_features = Some(features);
+        self
+    }
+
     /// Sets the font of this element and its children.
     fn font(mut self, font: Font) -> Self {
         let Font {

crates/markdown_preview/src/markdown_renderer.rs

@@ -75,8 +75,10 @@ impl RenderContext {
 
         let settings = ThemeSettings::get_global(cx);
         let buffer_font_family = settings.buffer_font.family.clone();
+        let buffer_font_features = settings.buffer_font.features.clone();
         let mut buffer_text_style = window.text_style();
         buffer_text_style.font_family = buffer_font_family.clone();
+        buffer_text_style.font_features = buffer_font_features;
         buffer_text_style.font_size = AbsoluteLength::from(settings.buffer_font_size(cx));
 
         RenderContext {
@@ -631,8 +633,14 @@ fn render_markdown_code_block(
         .tooltip(Tooltip::text("Copy code block"))
         .visible_on_hover("markdown-block");
 
+    let font = gpui::Font {
+        family: cx.buffer_font_family.clone(),
+        features: cx.buffer_text_style.font_features.clone(),
+        ..Default::default()
+    };
+
     cx.with_common_p(div())
-        .font_family(cx.buffer_font_family.clone())
+        .font(font)
         .px_3()
         .py_3()
         .bg(cx.code_block_background_color)