CVE-2021-3984: in findstartbrace() (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 inscomplgetexp() (edit.c), when CONTADDING is
active, only advance tmpptr by compllength if compl_length does not
exceed the remaining line length, so insert-mode completion no longer
reads past the end of the line.