Documentation for Dissolve states “This command works similar to the Melt command, the difference being, that unnecessary points will also be deleted automatically.”
The documentation for Melt states this for Edge mode: “Removes the selected edges; points that have become superfluous as a result are also deleted.”
In Broadcast R20, I can confirm that Melt of edges does remove unnecessary points as does Dissolve. So this appears to be a minor issue in the documentation. But is Dissolve now completely identical to Melt of edges? If so, probably don’t need that command anymore.