fix snippet rendering

Author: pikinier20

scaladoc/resources/dotty_res/styles/theme/color-tokens.css

@@ -60,7 +60,8 @@
   --code-syntax-highlighting-subst: var(--yellow11);
   --code-syntax-highlighting-meta: var(--yellow11);
   --code-syntax-highlighting-string: var(--lime9);
-  --code-syntax-highlighting-deletion: var(--purple9);
+  --code-syntax-highlighting-addition: var(--grass9);
+  --code-syntax-highlighting-deletion: var(--crimson11);
   --code-syntax-highlighting-variable: var(--purple9);
 
   --code-method-highlighting-type: var(--purple9);
@@ -137,7 +138,8 @@
   --code-syntax-highlighting-subst: var(--yellow11);
   --code-syntax-highlighting-meta: var(--yellow11);
   --code-syntax-highlighting-string: var(--lime9);
-  --code-syntax-highlighting-deletion: var(--purple9);
+  --code-syntax-highlighting-addition: var(--grass9);
+  --code-syntax-highlighting-deletion: var(--crimson11);
   --code-syntax-highlighting-variable: var(--purple9);
 
   --code-method-highlighting-type: var(--purple9);

scaladoc/resources/dotty_res/styles/theme/components/code-snippet.css

@@ -158,6 +158,10 @@
   color: var(--code-syntax-highlighting-deletion);
 }
 
+.hljs-addition {
+  color: var(--code-syntax-highlighting-addition);
+}
+
 .hljs-variable {
   color: var(--code-syntax-highlighting-variable);
 }

scaladoc/src/dotty/tools/scaladoc/renderers/DocRenderer.scala

@@ -64,7 +64,7 @@ class DocRender(signatureRenderer: SignatureRenderer)(using DocContext):
           case 5 => h5(cls := "h50")(content)
           case 6 => h6(cls := "h50")(content)
     case Paragraph(text) => p(renderElement(text))
-    case Code(data: String) => raw(SnippetRenderer.renderWikiSnippet(data))
+    case Code(data: String) => raw(SnippetRenderer.renderSnippet(data))
     case HorizontalRule => hr
     case Table(header, columns, rows) =>
       table(

scaladoc/src/dotty/tools/scaladoc/tasty/comments/markdown/SnippetRenderer.scala

@@ -156,11 +156,11 @@ object SnippetRenderer:
       node.compilationResult.fold(false)(_.isSuccessful)
     )
 
-  def renderWikiSnippet(content: String): String =
+  def renderSnippet(content: String, language: Option[String] = None): String =
     val codeLines = content.split("\n").map(_ + "\n").toSeq
     div(cls := "snippet mono-small-block")(
       pre(
-        code(
+        code(language.fold(Nil)(l => Seq(cls := s"language-$l")))(
           raw(wrapCodeLines(codeLines).map(_.toHTML).mkString)
         )
       ),

scaladoc/src/dotty/tools/scaladoc/tasty/comments/markdown/SnippetRenderingExtension.scala

@@ -29,9 +29,7 @@ object SnippetRenderingExtension extends HtmlRenderer.HtmlRendererExtension:
 
   object FencedCodeBlockHandler extends CustomNodeRenderer[FencedCodeBlock]:
     override def render(node: FencedCodeBlock, c: NodeRendererContext, html: HtmlWriter): Unit =
-      html.raw("""<div class="snippet">""")
-      c.delegateRender()
-      html.raw("""</div>""")
+      html.raw(SnippetRenderer.renderSnippet(node.getContentChars.toString, node.getInfo.toString.split(" ").headOption))
 
   object Render extends NodeRenderer:
     override def getNodeRenderingHandlers: JSet[NodeRenderingHandler[_]] =