Tidy suggestions for multipart name not found

Previously, the suggestion would involve making a string the length of
the entire multipart name starting at the beginning of the request. Now,
do not include this suggestion for a multipart name, and highlight only
the first word of it.
Avoid anonymous union in unicode patterns
Remove now-unused #pragma weak main
Add io.listdir method (code by Craig Forret)
Bump known-good
Restore #pragma weak main when main defined
Give egal access to confidential fields
Fix typo in structural dialect error message
Give error when "super" used as non-receiver
Allow super as LHS of operators