Syncing with fancyvrb: three new options

[muzimuzhi]

In its recent releases, fancyvrb has introduced three new options (see its Changes file), which minted may want to accept and pass on to fancyvrb too.

• vspace, added in v2.81 2011/04/06
• reflabel, added in v3.6 2020/05/03
• fileext, initially added as file_ext in v4.0 2021/11/19, then renamed to fileext in v4.2 2022/04/12

All these three options are light, thus compatible with fvextra.

[hvoss49]

The optional argument fileext is not documented because it was only introduced to remember to change the current behaviour:

the file extension is hardcoded in TeX:

\begin{VerbatimOut}{file}    ->  creates file.tex
\begin{VerbatimOut}{file.foo}    ->  creates file.foo

Maybe that I will come back to this issue in the future ...