Use lmodern LaTeX package for easier copying and pasting

latex/cpdt.tex

 \documentclass[12pt]{report}
 \usepackage[]{inputenc}
 \usepackage[T1]{fontenc}
+\usepackage{lmodern}
 \usepackage{fullpage}
 \usepackage{coqdoc}
 \usepackage{amsmath,amssymb}