Update manual for new time stamp format.

Update manual for new time stamp format.

These instances were missed the first time around.
Problem reported by Glenn Morris in <http://bugs.gnu.org/12706#25>.
* doc/lispintro/emacs-lisp-intro.texi (Files List):
* doc/lispref/buffers.texi (Modification Time):
* doc/lispref/files.texi (Testing Accessibility, File Attributes):
* doc/lispref/intro.texi (Version Info):
* doc/lispref/os.texi (Time of Day):
* doc/misc/emacs-mime.texi (time-date):
Update for new time stamp format (HIGH LOW MICROSEC PICOSEC).
* doc/misc/emacs-mime.texi (time-date):
Also, fix bogus time stamp and modernize a bit.