bug#10833: 24.0.93; Docstring of `scan-lists'

[Chong Yidong]

Michael Heerdegen <michael_heerdegen@web.de> writes:

> 1. The docstring of `scan-lists' needs to explain what "scanning" means.
>
> 2. This sentence is strange:
>
> "If the beginning or end of (the accessible part of) the buffer is reached
> and the depth is wrong, an error is signaled."
>
> What does "the depth is wrong" mean?  (I guess it's meant "the depth
> is not zero", at least the manual says that.)
>
> 3. See #10659 - Did you also adopt the docstring of `scan-lists'?

I've edited the docstring and the manual to make it clearer what the
scanner actually does.  Thanks.