Add toString to ModSettings and RemapConfigurationSettings (#831)

This helps a bit with debugging code that uses them as you don't
have to open the object to see which mod/remap configuration we're
investigating.

src/main/java/net/fabricmc/loom/api/ModSettings.java

@@ -122,4 +122,9 @@ public abstract class ModSettings implements Named {
 
 	@Inject
 	public abstract Project getProject();
+
+	@Override
+	public String toString() {
+		return "ModSettings '" + getName() + "'";
+	}
 }