CVE-2021-3984: in find_start_brace() (misc1.c), when a found '{' lies
inside a comment, restore the full cursor position (line and column)
instead of only the line so subsequent C-indent lookups stay within
the line bounds.
CVE-2022-2571: in ins_compl_get_exp() (edit.c), when CONT_ADDING is
active, only advance tmp_ptr by compl_length if compl_length does not
exceed the remaining line length, so insert-mode completion no longer
reads past the end of the line.