Fix a comment.

Fix a comment.

Ligating of -- to en dashes occure also in teletype fonts.
With some 8-bit fonts, em and en dashes are not copied
exported from the PDF (but this is not limited to dashes in teletype).
With LatinModern, PDF export works fine
MWE:
\documentclass[]{article}
%\usepackage{lmodern}
\usepackage[T1]{fontenc}
\begin{document}
Hallo \texttt{Welt --Welt ---Welt}
Hallo Welt --Welt ---Welt