code: private void parseElementDecl() throws Exception {
          String name;
  
          requireWhitespace();
          // Read the element type name.
          name = readNmtoken(true);
  
          requireWhitespace();
          // Read the content model.
          parseContentspec(name);
  
          skipWhitespace();
          require('>');
      }
docs: Parse an element type declaration.
  
  <pre>
  [45] elementdecl ::= '&lt;!ELEMENT' S Name S contentspec S? '&gt;'
  </pre>
  
  <p>
  NOTE: the '&lt;!ELEMENT' has already been read.