Instead of an error during G tool, use Alt+J tool

[openstreetmap.org-user-d1g]

Consider a way with 3 nodes:

o---X---o

If G used on big X, then JOSM will show an error. But why? We could simply use Alt+J logic here.

Same for:

o---X---X---X---X---X---X---X---X---X---X---o

Less shortcuts = simpler activation and time saving.

Only one thing that would be left in (Alt+J) is usage on leaf nodes:

X---o---o

Could be replaced with Ctrl+Delete mode (remove a segment, not "DisconnectNodeWay")

o---o---X

Could be replaced with Ctrl+Delete mode (remove a segment, not "DisconnectNodeWay")