Sets `AlignOperands` to `DontAlign`.
`clang-format` developers seem to mostly care about space-based indentation and
every other version of clang-format breaks the bad mismatch of tabs and spaces
that it seems to use for operand alignment. So it's better without, so that it
respects our two-tabs `ContinuationIndentWidth`.
`#pragma once` was used in a few files, yet we settled on using
traditional include guards instead.
The PooledList template comment was also moved to allow editors
such as Visual Studio Code to display the comment when hovering
PooledList.
`app.h` was renamed to `app_uwp.h` to be less generic for the
include guard.
