Issue #4248: Close Scissors Select curve when pressing Enter
This attempts to resolve issue #4248.
You can currently press Enter once a curve is closed to convert it to a selection. Unlike the path tool however, pressing it when the curve is not yet closed does nothing. This patch attempts to resolve the issue and align behaviors by closing the curve on Enter if the following conditions are met:
- There are at least 3 nodes created for the selection
- The first and last node are not the same
Pressing Enter a second time turns the curve into a selection as usual.