Adds tooltip descriptions for a few map generator settings. The tooltips
are limited to dropdown choices. No tooltips are added for the options
containing the choices or any non-dropdown settings.
- Terrain type
- Bounds shape
- Buildings
The "Square" bounds shape is rephrased as "Rectangle" for consistency
with the added description.
This is UI-only change.
The terms "width" and "height" are clearer and they match what the values actually represent (window or parent width/height). The YAML changes are generated with the update rule.
