typing: adjust placement of type comments for multi-line statements further

With py3.6.9 or py3.7.5 and pytype 2020.9.16, this was getting flagged for me
after 8d4381a39485.  So lets keep both for now.

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branch : stable
10 jobs for 5.5.2 in 48 minutes and 33 seconds (queued for 2 seconds)
latest
Status Job ID Name Coverage
  Test
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pytype-py3-hg-default

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pytype-py3-hg-stable

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tests-py2-hg-default

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tests-py2-hg-stable

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tests-py3-hg-5.4

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tests-py3-hg-default

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tests-py3-hg-stable

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