swift234

Fix <rdar://14296004> [QoI] Poor diagnostic/recovery when two operators (e.g., == and -) are adjacted without spaces.

This is a frequently reported and surprising issue where lack of whitespace leads to
rejecting common code like "X*-4".  Fix this by diagnosing it specifically as a lack
of whitespace problem, including a fixit to insert the missing whitespace (to transform
it into "X * -4".  This even handles the cases where there are multiple valid (single)
splits possible by emitting a series of notes.