History of font-weight

Followup on previous edit, which was mistakenly submitted while incomplete, attempting to add line breaks to revision comment. In short, I provided technical review of the "Fallback" section, ensuring that it matches the specifications it paraphrases.

In response to the need for technical review. In the section "Fallback", the fourth bullet was previously edited to say:

Fallback heuristics don't make sense, I've edited them to the most logical sounding option.

adjusting height

converting sample

Replaced 'csssyntax2' macro by 'csssyntax' again

Replaced 'cssbox' by 'cssinfo'