Fixup string concatenations

[blag]

This PR just fixes a few string concatenations here and there. Please pay particular attention to the regexes that I tweaked.

I may have been a little overzealous with my changes, namely:

• It seems like sometimes explicit string concatenation was done to differentiate a line from its surroundings. I'm not sure if we want to keep things that way, or force everything to use implicit concatenation.
• I also reformatted some of the SQL statements to (IMO) make them a bit more readable.

I also updated the tabulate dependency from 0.8.7 to 0.8.8 to fix an issue when attempting to run unit tests under Python 3.10. Those tests still fail for other reasons but this is one less speed bump when we add that, however, I'm not sure if including that change is appropriate in this PR.

[boring-cyborg]

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[github-actions]

The PR most likely needs to run full matrix of tests because it modifies parts of the core of Airflow. However, committers might decide to merge it quickly and take the risk. If they don't merge it quickly - please rebase it to the latest main at your convenience, or amend the last commit of the PR, and push it with --force-with-lease.

[boring-cyborg]

Awesome work, congrats on your first merged pull request!

[jedcunningham]

@blag, congrats on your first commit 🍺

[blag]

Thanks, cheers! 🍺