Review ad-hoc suppression of blank lines

[lkrms]

• Consider statements like these for replacement with suppression of blank lines across a range of tokens, so blank lines between adjacent comments are collapsed in the given context:

  • $token->Whitespace |= Space::NO_BLANK_...
  • $items->setTokenWhitespace(Space::NO_BLANK_...)

• Don't downgrade blank lines to newlines in PreserveNewlines::maybePreserveNewlineAfter(). It would be preferable for newlines in the input to be preserved as-is, and for blank lines to be suppressed as needed, so presets and (future) third-party rules can preserve blank lines that are suppressed by default.