* search.c (find_newline): Return byte position in bytepos.

* search.c (find_newline): Return byte position in bytepos.
Adjust comment.
(find_next_newline_no_quit, find_before_next_newline): Add
bytepos argument.
* lisp.h (find_newline, find_next_newline_no_quit)
(find_before_next_newline): Adjust prototypes.
* bidi.c (bidi_find_paragraph_start):
* editfns.c (Fconstrain_to_field, Fline_end_position):
* indent.c (compute_motion, vmotion):
* xdisp.c (back_to_previous_line_start, forward_to_next_line_start):
(get_visually_first_element, move_it_vertically_backward):
Adjust users and avoid calls to CHAR_TO_BYTE where appropriate.