`//`(Floor Division) on CockroachDB query formatting fixed

[jonasbadstuebner]

The floor division opeator // is special to CockroachDB I think. I found it in other DBMS' Documentation but only for comments (and none of them are officiall supported by sqltools), so keeping these two slashes without whitespace inbetween no matter what should always at least be "more valid" than splitting them apart. Therefore I do not expect unwanted side effects because of this change.

fixes #1234

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• [x] Your code builds clean without any errors or warnings There are warnings, but not because of my change
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[gjsjohnmurray]

We just published 0.28.1 with this change included. Thanks again!