Where is the convention to mark a symbol with `' in comments comes from?

Question

I see this both in man page and in emacs lisp doc string, it looks like a convention; is there a formal document about that?

what contexts should I follow this rule?

Answer 1

@lawlist has answered wrt where you can find the doc about this.

The reason for this convention is that it allows the code that composes a help buffer to recognize things for what they are: variables, functions, macros, keys, etc., and put links on them to take you to other help buffers. Without the convention it is much more problematic trying to determine whether foo refers to variable foo, function foo etc.