syntax highlighting / code block for other than default programming language list

## Is your feature request related to a problem? Please describe.

At Zenodo upload, additional description can be added of type "Technical info". This allows inclusion of a code block, but only a selective list of default programming languages is available and no option for "unspecified" language.

## Describe the solution you'd like

1. Provide a "unspecified" option in the list which does not do syntax highlighting but allows to include a code block where the code is formatted in a monospaced typeface font
2. My use case would be to include a code block for the R programming language (which is also fairly popular in data science and especially statistical data analysis). So the option to select R syntax highlighting would be highly appreciated as well.

## Describe alternatives you've considered

I currently use the "quote" tool to include my R code.

## Additional context

Screenshots:


What I would like is press the "{;}" button and have the option to select "R" and/or "unspecified". This is currently not possible: