Typo bug in the AddNonIdealMHDFlux function

[jeankpf]

Hello there,

I noticed a weird line in the AddNonIdealMHDFlux function of the current master branch. https://github.com/idefix-code/idefix/blob/158f2aa3a35148bb2a992ae24bb8f813a5965034/src/fluid/addNonIdealMHDFlux.hpp#L261 I think it should rather be something like: localdmax += eta; to be consistent with the meaning of the dMax array, and the rest of the code in this function.

Cheers, Jean