I should be able to easily show a block of QL

Summary: Requested by Eric, but heavens knows I want it too -- showing some QL as text is way too much of a pain in the ass.

We considered something like six backticks, but that fails because it's at the wrong level -- that a QText solution for a fundamentally QL problem, and the QL gets evaluated first. (Besides, the QText parser is much more fragile and dangerous to work with.

But here's a theory: we could add the three-backtick mechanism inside of QL. When used in there, it takes everything in there and renders it as a block of QText surrounded by triple-ticks, entirely skipping any QL parsing below that level. In principle, that seems easy -- there are going to be some inevitable edge cases (like when the contained block has its own triple-ticks somewhere), but it should cover most cases straightforwardly.