Comment # 1 on bug 1202949 from Christophe Giboudeaux

# LANG=C zypper in cmark-devel
Loading repository data...
Reading installed packages...

The following 3 NEW packages are going to be installed:
  cmark cmark-devel libcmark0_30_2


The solver is right. cmark doesn't depend on python3-commonmark but
python3-commonmark conflicts with cmark.

Just choose the solution 1.