@konsumlamm pretty please: consider sending PR's instead; too many bugs to keep track of and this falls under the umbrella "docs should improve"

I would start with the procs that would benefit most from having doc comment, especially if there's some gotcha; and I'd focus on the gotchas to make the docs useful and not redundant

• <= seems low priority (compared to other procs) as it should be obvious, no gotcha;
• * has a gotcha so is worth mentioning (eg; overflow checks with signed integers)
• cas is a terrible non-descriptive name for a proc defined in system (and probably shouldn't be in system but in some other module); either way a doc comment helps here (and maybe deprecating it later)
• use runnableExamples as needed; often an example is the simplest / most concise explanation
• how about start with these one:

proc `|`(a, b: typedesc): typedesc =
  runnableExamples: doAssert int is float | int

• start with just 1 or a few at first just to get some feedback before doing more

oh, and thanks for #14737 ; I will follow-up there