(derived-mode-p): Take MODES as a single argument

(derived-mode-p): Take MODES as a single argument

Looking at uses of `derived-mode-p` and `provide-mode-derived-p`,
I can't find a single use case where it wouldn't be preferable for
it to take a single argument instead of `&rest`: all the calls are
either passing a single argument anyway, or passing a fixed list of modes.
The use of `&rest` just makes the code less efficient and sometimes
more clunky (because of the need for `apply`).
So let's change that (while preserving backward compatibility, of course).

* doc/lispref/modes.texi (Derived Modes): Adjust accordingly.

* lisp/subr.el (provided-mode-derived-p, derived-mode-p): Take the
`modes` as a single argument.