Bug in removal of comments
\documentclass{article}
\begin{document}
Sentence ends with the abbreviation U.S.A\@%
. Next sentence
\end{document}
gives
\documentclass{article}
\begin{document}
Sentence ends with the abbreviation U.S.A\@ . Next sentence
\end{document}
which is wrong. The output should be
\documentclass{article}
\begin{document}
Sentence ends with the abbreviation U.S.A\@. Next sentence
\end{document}