Move highway=busway into 'Traffic Roads' map features group

[Rewinteer]

Since highway=busway proposal was approved, such features became quite popular in some regions (for example, the Netherlands).

Now in iDEditor this type of ways is visible only when the 'Other Features' checkbox of Map Features menu is enabled. This could lead to mapping mistakes, because it is logical to enable 'Traffic Roads', 'Service Roads' checkboxes while reviewing road network, so it is easy to draw a new road over existing busway that will not be visible in this case. OSM Carto also doesn't render busways yet and it is even easier to get wrong with that.

I believe it would be more logical to place highway=busway features to 'Traffic Roads' group, since the proposal linked above says that busways are not comply with service roads definition (so 'Service Roads' group doesn't fit such objects), but busways apparently are traffic roads, but opened only to certain groups of vehicles.