Note about the overlapping and combination of different NetworkChaos

[STRRL]

One loss NetworkChaos and another delay NetworkChaos would not affect on one pod at the same time, the post one would overwrite the former one.

User should use action: netem to inject the combination NetworkChaos, which should be mentioned in the documentation.

https://github.com/chaos-mesh/chaos-mesh/issues/3631#issuecomment-1251352396