This closes#7459.
While emoji don’t actually need escaping, expanding the
expression that enumerates all task name characters that
don’t need escaping to include emoji is prohibitive, since
it’s a discontinuous range. The emoji-regex project has
such an expression and it’s 12kB.
This fixes the regular expression to property escape emoji
as a single character instead of as its component bytes.
Thanks to @DingoEatingFuzz for the suggestion.
e3392b7da8