More fixes in the Emacs manual

More fixes in the Emacs manual

* doc/emacs/screen.texi (Mode Line): Fix markup and
cross-references.
(Menu Bar): Correct inaccurate description.
* doc/emacs/macos.texi (Mac OS / GNUstep, Mac / GNUstep Events):
* doc/emacs/frames.texi (Scroll Bars):
* doc/emacs/emacs.texi (Top):
* doc/emacs/ack.texi (Acknowledgments): Fix spelling of "macOS".
* doc/emacs/misc.texi (Invoking emacsclient)
(emacsclient Options): Fix markup of 'emacsclient'.  Suggested by
Michael Albinus <michael.albinus@gmx.de> in
emacs-manual-bugs@gnu.org.