Re #6270 Step 1, provide `--haddock-for-hackage` #2291

Job	Run time
Pedantic	23m 51s
Unit tests (ubuntu-latest)	19m 44s
Unit tests (ubuntu-latest, alpine, --docker --system-ghc --no-install-ghc --flag stack:static)	20m 30s
Unit tests (windows-latest)	6m 21s
Unit tests (macos-latest)	7m 47s
	1h 18m 13s

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