Enable clang-format AlignConsecutiveMacros.

[Stephan T. Lavavej (StephanTLavavej)]

Description

• Update .clang-format defaults.

• Enable AlignConsecutiveMacros, newly supported by clang-format 9. We often followed this style before using clang-format, and I believe that it produces generally positive changes.

• Apply clang-format changes.

• Replace _FITS and _NEXT_ALIGN macros. clang-format didn't damage them, it just brought them to my attention. These macros weren't improving clarity, and the code is more systematic without them. (For the time being, I have refrained from further overhauling the metaprogramming here.)

Checklist

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[Billy O'Neal (BillyONeal)]

I am not a fan of this alignment for the same reason I'm not a fan of the 'align assignments' setting we've been using. But I care a lot less about how we format stuff than you do, so I guess this is OK.