[css-fonts-4] Matching algorithm for weights 400 and 500 misses a step

[litherum]

https://drafts.csswg.org/css-fonts/#font-matching-algorithm

"If the desired weight is 400, 500 is checked first ..."
"If the desired weight is 500, 400 is checked first ..."

I think what it means to say is:
"If the desired weight is 400, 400 is checked first, 500 is checked second, ..."
"If the desired weight is 500, 500 is checked first, 400 is checked second, ..."