SQL: Quoted variables are now greedy

[RunDevelopment]

This resolves #1509.

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I added a small fix to bypass #1492.
It now (mostly) works because the quoted variables are now matched before strings. Therefore strings (of quoted variables) are always contained by the variable which leads to there match being discarded.

This little trick also reduces the greedy matching overhead because it doesn't have to rematch any patterns. Maybe we should include this trick into the docs as a best practice?

[mAAdhaTTah]

Got conflicts here, probs a result of the other SQL PR I just merged.

[mAAdhaTTah]

Are there styles for quoted-variable? I don't think that's a currently-existing token...

[RunDevelopment]

I know any styles for quoted-variable either. It's just a temporary name because it has to be matched before string.
But we could move variable before string as well and merge the two into one variable token without any side effects (I think).

[mAAdhaTTah]

Give that a shot if you think it's feasible. I'd definitely like to avoid introducing new tokens used in a single language, if possible.

[RunDevelopment]

I did implement the merged variable token.

Is it ready to merge then?