Web Applications 1.0 r6925 Add a note about <li><h1>.Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=14486

Add a description of Web Applications 1.0 r6925 Add a note about <li><h1>.Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=14486