[Doc] No syntax highlighting for Python in Doxygen

[stwunsch]

We are missing syntax highlighting for Python code blocks in Doxygen, see the snippet from the RDataFrame docs below:

Afaik, the code block is correctly tagged with the language:

https://github.com/root-project/root/blob/master/tree/dataframe/src/RDataFrame.cxx#L447

[vepadulano]

I tried with ~~~{.py} on my local machine and it rendered the python blocks with highlighted syntax. It's still is quite poorly done compared to the cpp blocks, but I think that's just how doxygen does it

[vepadulano]

If you want I can open a PR with the changes

[stwunsch]

Ah nice, so it's the wrong keyword 😬 Thanks for pointing this out! I'll take care of it :)