Update docgen style (#6723)
Update docgen style (#6723)

Switch to Lato font for better readability
Make text darker
Make spacing between paragraph and pre block consistent
Fix search input box to prevent overlapping with text
dom96/Nim,dom96/Nim,dom96/Nim,russpowers/Nim,russpowers/Nim,dom96/Nim,dom96/Nim,russpowers/Nim,russpowers/Nim,dom96/Nim,dom96/Nim,russpowers/Nim,russpowers/Nim,russpowers/Nim