Skip HTML comments when computing synopsis

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: garazdawi

lib/ex_doc/doc_ast.ex

@@ -166,6 +166,7 @@ defmodule ExDoc.DocAST do
     to_html({:p, [], remove_ids(inner), meta})
   end
 
+  def synopsis([{:comment, _, _, _} | rest]), do: synopsis(rest)
   def synopsis([head | _]), do: synopsis(head)
   def synopsis(_other), do: ""
 

test/ex_doc/doc_ast_test.exs

@@ -147,6 +147,10 @@ defmodule ExDoc.DocASTTest do
                "<p>Example function: Summary should display trailing period :.</p>"
     end
 
+    test "skips html comments" do
+      assert synopsis("<!-- comment -->\nSynopsis.") == "<p>Synopsis.</p>"
+    end
+
     defp synopsis(markdown) do
       markdown
       |> parse!("text/markdown")