Fix comment regex

[oashour]

This PR fixes an issue with the comment stripping regex that would strip the character before a comment if there was no space.

This caused issues with parsing figure names if the .tex file looked like, e.g.,

\begin{figure}
\includegraphics[\linewidth]{myfig.pdf}%
\caption{whatever}
\end{figure}

, the }% would be stripped, leading to the imgname being myfig.pdf\n\caption{whatever.

[corettialessandro]

This is quite important, I recommend merging this PR. My estimate was over by 140 words due to this issue. @oashour Maybe also open an issue and link the PR so that it is easier to find. Thanks for the solution btw