This option does not set the absolute speed of the entity as the name
implies. It sets a modifier. The default (vanilla) value of `0.5` sets
the baby zombie to move at 50% faster than the base speed.
A negative value like `-0.4` would set them to move at 40% slower.
There should be no functional changes as a result of this change, it's
just clarifying the config name.
MiniDigger
Zach Brown