feat(highlight): syntax-highlight qmd comments in Monaco

HTML `<!-- -->` and editorial `[>> ...]` comments now emit a
qmd.markup.comment semantic token (muted italic) via a new highlights.scm
capture, legend entry (Rust + TS), and theme rule.

Snapshots: 1 modified (structural_corpus, +2 lines) — the two corpus
comments now resolve to qmd.markup.comment; no other tokens changed.

Author: shikokuchuo

crates/quarto-lsp-core/src/snapshots/quarto_lsp_core__tokens__tests__structural_corpus.snap

@@ -55,3 +55,5 @@ expression: rendered
 33:0-6 qmd.code.keyword
 33:7-9 qmd.code.variable
 34:0-3 qmd.punctuation.delimiter.fence
+36:2-26 qmd.markup.comment
+36:32-52 qmd.markup.comment

crates/quarto-lsp-core/src/tokens.rs

@@ -497,6 +497,47 @@ mod tests {
         assert!(has_type(&toks, "qmd.attribute.specifier"), "got {toks:?}");
     }
 
+    #[test]
+    fn tokens_for_html_comment() {
+        // `<!-- ... -->` parses to a `comment` node; the whole span is coloured.
+        // The grammar's comment token swallows the preceding space, so assert
+        // the meaningful edge: a comment token reaching the end of `-->` (col 20)
+        // and starting no later than the `<` (col 5).
+        let toks = tokens("Text <!-- hidden --> more\n");
+        assert!(
+            toks.iter().any(|t| type_name(t) == "qmd.markup.comment"
+                && t.line == 0
+                && t.character <= 5
+                && t.character + t.length == 20),
+            "expected a markup.comment over `<!-- hidden -->`, got {toks:?}"
+        );
+    }
+
+    #[test]
+    fn tokens_for_multiline_html_comment_split_at_lines() {
+        // A comment spanning lines must be split into per-line tokens.
+        let toks = tokens("<!--\nhidden\n-->\n");
+        let comments: Vec<_> = toks
+            .iter()
+            .filter(|t| type_name(t) == "qmd.markup.comment")
+            .collect();
+        assert_eq!(
+            comments.len(),
+            3,
+            "expected one comment token per line, got {toks:?}"
+        );
+    }
+
+    #[test]
+    fn tokens_for_edit_comment() {
+        // Quarto editorial comment `[>> ...]` parses to an `edit_comment` node.
+        let toks = tokens("Para [>> editorial note]\n");
+        assert!(
+            has_type(&toks, "qmd.markup.comment"),
+            "expected a markup.comment for `[>> ...]`, got {toks:?}"
+        );
+    }
+
     #[test]
     fn tokens_are_non_overlapping_and_sorted() {
         // A link inside a heading deliberately nests, exercising the flatten.

crates/quarto-lsp-core/src/types.rs

@@ -644,6 +644,7 @@ pub static QMD_TOKEN_LEGEND: &[&str] = &[
     "qmd.markup.shortcode",
     "qmd.markup.list",
     "qmd.markup.quote",
+    "qmd.markup.comment",
     "qmd.punctuation.special",
     "qmd.punctuation.special.image",
     "qmd.punctuation.bracket",

crates/quarto-lsp-core/tests/fixtures/highlight-corpus.qmd

@@ -33,3 +33,5 @@ x <- 1
 ```python
 import os
 ```
+
+An <!-- inline comment --> and a [>> editorial note].

crates/tree-sitter-qmd/tree-sitter-markdown/queries/highlights.scm

@@ -80,6 +80,12 @@
 ; --- Raw inline/block HTML ---------------------------------------------------
 (html_element) @markup.raw
 
+; --- Comments (HTML `<!-- -->` and editorial `[>> ...]`) ---------------------
+[
+  (comment)
+  (edit_comment)
+] @markup.comment
+
 ; --- Fenced code: delimiter + info string (interior left to zone 3) ----------
 (fenced_code_block_delimiter) @punctuation.delimiter.fence
 (info_string) @markup.raw.info

crates/wasm-quarto-hub-client/Cargo.lock

@@ -66,6 +66,7 @@ export const quartoThemeRules: Monaco.editor.ITokenThemeRule[] = [
   { token: 'qmd.markup.shortcode', foreground: FUNCTION },
   { token: 'qmd.markup.list', foreground: PUNCT },
   { token: 'qmd.markup.quote', foreground: COMMENT, fontStyle: 'italic' },
+  { token: 'qmd.markup.comment', foreground: COMMENT, fontStyle: 'italic' },
   { token: 'qmd.punctuation.special', foreground: PUNCT },
   { token: 'qmd.punctuation.special.image', foreground: IMAGE_ACCENT },
   { token: 'qmd.punctuation.bracket', foreground: BRACKET },

hub-client/src/components/quartoTheme.ts

@@ -56,6 +56,7 @@ export const QMD_TOKEN_LEGEND: readonly string[] = [
   'qmd.markup.shortcode',
   'qmd.markup.list',
   'qmd.markup.quote',
+  'qmd.markup.comment',
   'qmd.punctuation.special',
   'qmd.punctuation.special.image',
   'qmd.punctuation.bracket',

hub-client/src/services/intelligenceService.ts

@@ -79,6 +79,20 @@ describe('lsp_get_semantic_tokens', () => {
     expect(codeOnBody.length).toBeGreaterThan(0);
   });
 
+  it('produces a comment token for an HTML comment', () => {
+    const result = tokensFor('Text <!-- hidden --> more\n');
+    expect(result.success, result.error).toBe(true);
+    const names = (result.tokens ?? []).map(typeName);
+    expect(names).toContain('qmd.markup.comment');
+  });
+
+  it('produces a comment token for an editorial `[>> ...]` comment', () => {
+    const result = tokensFor('Para [>> editorial note]\n');
+    expect(result.success, result.error).toBe(true);
+    const names = (result.tokens ?? []).map(typeName);
+    expect(names).toContain('qmd.markup.comment');
+  });
+
   it('returns an empty token list for an empty document', () => {
     const result = tokensFor('');
     expect(result.success).toBe(true);