Makes Setting class world name default user underscore

config.yml had "BSkyBlock_world" as the name but the Settings class had
"BSkyBlock-world" so if the config.yml was deleted, the default one
could end up being used.

https://github.com/BentoBoxWorld/BSkyBlock/issues/107

pom.xml

@@ -6,7 +6,7 @@
 
 	<groupId>world.bentobox</groupId>
 	<artifactId>bskyblock</artifactId>
-	<version>1.4.1</version>
+	<version>1.4.2</version>
 
 	<name>BSkyBlock</name>
 	<description>BSkyBlock is an add-on for BentoBox, an expandable Minecraft Bukkit plugin for island-type games like SkyBlock or AcidIsland.</description>

src/main/java/world/bentobox/bskyblock/Settings.java

@@ -47,9 +47,9 @@ public class Settings implements DataObject, WorldSettings {
     private String friendlyName = "BSkyBlock";
 
     @ConfigComment("Name of the world - if it does not exist then it will be generated.")
-    @ConfigComment("It acts like a prefix for nether and end (e.g. BSkyBlock-world, BSkyBlock-world_nether, BSkyBlock-world_end)")
+    @ConfigComment("It acts like a prefix for nether and end (e.g. BSkyBlock_world, BSkyBlock_world_nether, BSkyBlock_world_end)")
     @ConfigEntry(path = "world.world-name")
-    private String worldName = "BSkyBlock-world";
+    private String worldName = "BSkyBlock_world";
 
     @ConfigComment("World difficulty setting - PEACEFUL, EASY, NORMAL, HARD")
     @ConfigComment("Other plugins may override this setting")