In-line math: Markup type mmark is deprecated

[ulrich-schroeders]

KaTex is working fine for "block math" and the usual markdown-file (*.md).
However, to get "inline math" working properly (= without line break) you have to use *.mmark, which is going to "[...] be removed in a future release. See https://gohugo.io//content-management/formats/#list-of-content-formats".

Any thoughts on this issue?