New cop: MultilineBlockLayout
Merge pull request #1079 from barunio/newline_after_multiline_block_start

New cop: MultilineBlockLayout
[Fix #1210] Fix false positive in UnneededPercentQ for %Q(\t")

We've said that %Q can be used for dynamic strings that contain
double quotes. Dynamic strings must include strings with special
characters such as \t and \n, not only strings with interpolation.
Make UnneededPercentQ spec easier to read

There were so many kinds of strings. It got complicated,
so a few heredoc strings are helpful, I think.
Fix false positive for heredoc strings in UnneededPercentQ