Don't insert empty line when translating QuoteInsets to literal
quotes.
Fix regexp pattern in re/convert_dashligatures.
Adjust logic in re/convert_dash(ligatur)es.
* use unicode.transform() instead of loop over replacements
* telling variable names
* remove trailing whitespace
* documentation update
* don't set use_ligature_dashes if both dash types are found
* remove spurious warning, normalize indentation, and use
Python idioms in revert_baselineskip()