Thorough Review should mention depth as well as breadth

[fantasai]

Thorough Review: We ensure the technical standards of the Web use broad and consistent horizontal review to ensure fundamental attributes such as accessibility, internationalization, sustainability, privacy, security, technical soundness, and architectural integrity.

This misses that we do deep review as well as wide review.

Also maybe it should use the word "wide" since that's the keyword we use elsewhere to capture the idea of "broad" review?

[mgendler]

Moving some thoughts here in case people aren't following the pr at #229

@fantasai I'm not particularly comfortable with dropping the adjectives and just saying "through consistent review." I think it's a pretty strong part of our work at the W3C that there are workflows and sometimes additional norms around getting wide and horizontal review. I don't mind the word wide instead of broad, but horizontal review carries a very specific meaning in my mind and I think gives a clear indication of the way our standards body works.

Similarly, I don't love dropping the two descriptors for 'thorough' as I think it's significantly more vague.