QueryParser corner cases

[olly]

There are quite a few cases which we probably don't handle as well as we could (sometimes it's not totally clear what the behaviour should be), so let's make a list here and see if we can find resolutions, or decide the current behaviour is fine.

With FLAG_SYNONYM these cause reparsing so parse as foo abc def (we just ignore ~ unless the next character is a word character, so without the "foo:" prefix, ~ is just ignored):

~foo:(abc def)
~foo:"abc def"