pandoc/test/command/5836.md

```
% pandoc -f markdown -t latex
\newcommand{\vara}{\alpha}
\newcommand{\varb}{b}
$\vara \varb$
^D
\newcommand{\vara}{\alpha}
\newcommand{\varb}{b}

\(\alpha b\)
```
```
% pandoc -f latex -t latex
\newcommand{\vara}{\alpha}
\newcommand{\varb}{b}
$\vara \varb$
^D
\(\alpha b\)
```
```
% pandoc -f latex -t latex
\newcommand{\vara}{\alpha}
\newcommand{\varb}{b}
\[\vara \varb\]
^D
\[\alpha b\]
```