Minor correction in the XHTML output

While a post-processor interface to the HTML validator, I encountered a
really small detail in the HTML output. For valid and invalid result,
the output contains an H2 element with @id=result. This is not the case
for fatal errors, where @class=fatal is on the div and no element has
@id=result. Not a big deal to provide a work-around in my post-processor
but you may want to harmonize the outputs.

Philippe