Is your feature request related to a problem? Please describe it.
Currently, conceal is enabled in \newcommand and \renewcommand (and \providecommand and so on...), which means
this command:

\renewcommand\emph{\textbf}

will be displayed as:

\renewcommand

which is very confusing.

Describe the solution you'd like
I've noticed that conceal is disabled inside verbatim environments. I'm not sure how it's done but maybe we could
use the same method to implement an interface for users to disable conceal inside specific commands/environments.