Make QuickStatements check for correct use of tabs before making changes

[96187]

Right now QuickStatements doesn't check whether the line is valid until it gets to it, which means if you accidentally have a space instead of a tab (easily done, since they're not easy to distinguish), it errors and breaks in the middle of what you're doing (particularly annoying if you're using LAST).

I think it would be better if it checked before starting that the structure looks OK. If I followed the explanation correctly, I think checking that each line matches the following should work:

^(CREATE|MERGE\tQ[0-9]+\tQ[0-9]+|[^\t]+\tP[0-9]+\t[^\t]+(\t[PS][0-9]+\t[^\t]+)*|[^\t]+\t[LDAS][a-z_]+\t"[^\t]+")$