Add more clarity around bold 600 decision
Its not clear from looking at pajamas what font weight we use for bold text. You have to inspect the text or find the variable in GitLab UI.
We should include the variable name and it's value on the typography page. We can also include explanatory text that explains why we use 600 over 700
It’s because some system fonts have a semi-bold, which would be mapped to 600, and that weight was preferred. For system fonts without a semi-bold it would be mapped to the 700 weight, which is why it could look extra bold in other OSs.