DiffViewer: lines color by their file's syntax; prose reads plain (Ely R2.12)

src/editor/mod.rs

@@ -60,6 +60,6 @@ pub use status::{
     LspStatus, NotificationBell,
 };
 pub use symbols::{Call, CallHierarchy, GoToSymbol, Symbol, SymbolKind, SymbolOutline};
-pub(crate) use syntax::colors as code_colors;
+pub(crate) use syntax::{colors as code_colors, colors_with as code_colors_with};
 pub use tasks::{Task, TaskRunner, TaskState};
 pub use welcome::{Project, ProjectSwitcher, RecentProjects, WelcomePage};

src/editor/syntax.rs

@@ -3,7 +3,7 @@ use std::ops::Range;
 use gpui::{App, HighlightStyle};
 
 use super::buffer::Buffer;
-use crate::forms::{Kind, code_highlights, lex};
+use crate::forms::{Kind, code_highlights_with, lex};
 
 /// Each line that opens a block, and the last line the block holds, read from indentation.
 pub(crate) fn folds(buffer: &Buffer) -> Vec<(usize, usize)> {
@@ -110,7 +110,16 @@ pub(crate) fn matched(brackets: &[Bracket], caret: usize) -> Option<(usize, usiz
 
 /// A line's syntax colors as highlight styles.
 pub(crate) fn colors(text: &str, cx: &App) -> Vec<(Range<usize>, HighlightStyle)> {
-    code_highlights(text, cx)
+    colors_with(text, "//", cx)
+}
+
+/// Colors for a line whose comments start with `comment`.
+pub(crate) fn colors_with(
+    text: &str,
+    comment: &str,
+    cx: &App,
+) -> Vec<(Range<usize>, HighlightStyle)> {
+    code_highlights_with(text, comment, cx)
         .into_iter()
         .map(|(range, highlight)| {
             (