Fix the bytecode incompatibility due to the change to 'narrow-to-region'.

Fix the bytecode incompatibility due to the change to 'narrow-to-region'.

* src/editfns.c (narrow_to_region_internal): New function, which
contains the body previously in 'Fnarrow_to_region' but accepts
a third argument.
(Fnarrow_to_region): Use the new function. Update the docstring.
(Fwiden): Update the docstring.

* src/lisp.h: Prototype of the new function.

* src/xdisp.c (handle_fontified_prop): Use the new function instead
of 'Fnarrow_to_region'.

* src/process.c (Finternal_default_process_filter):
* src/lread.c (readevalloop): Remove the third argument to
'Fnarrow_to_region'.

* src/bytecode.c (exec_byte_code):
* lisp/emacs-lisp/comp.el (comp-limplify-lap-inst):
* lisp/emacs-lisp/bytecomp.el: Restore the statu quo ante.

* etc/NEWS: Remove the entry about the new optional argument.

* doc/lispref/positions.texi (Narrowing): Update the documentation.