Updated Upstream (Bukkit/CraftBukkit/Spigot)

Upstream has released updates that appears to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing

Please note that this build includes changes to meet upstreams
requirements for nullability annotations. While we aim for a level of
accuracy, these might not be 100% correct, if there are any issues,
please speak to us on discord, or open an issue on the tracker to
discuss.

Bukkit Changes:
9a6a1de3 Remove nullability annotations from enum constructors
3f0591ea SPIGOT-2540: Add nullability annotations to entire Bukkit API

CraftBukkit Changes:
8d8475fc SPIGOT-4666: Force parameter in HumanEntity#sleep
8b1588e2 Fix ExplosionPrimeEvent#setFire not working with EnderCrystals
39a287b7 Don't ignore newlines in PlayerListHeader/Footer

Spigot Changes:
cf694d87 Add nullability annotations

Spigot-API-Patches/Add-an-asterisk-to-legacy-API-plugins.patch

@@ -7,7 +7,7 @@ Not here to name and shame, only so server admins can be aware of which
 plugins have and haven't been updated.
 
 diff --git a/src/main/java/org/bukkit/UnsafeValues.java b/src/main/java/org/bukkit/UnsafeValues.java
-index a4aabfe7..f462b631 100644
+index a4aabfe7f..f462b631b 100644
 --- a/src/main/java/org/bukkit/UnsafeValues.java
 +++ b/src/main/java/org/bukkit/UnsafeValues.java
 @@ -0,0 +0,0 @@ public interface UnsafeValues {
@@ -22,7 +22,7 @@ index a4aabfe7..f462b631 100644
 +    // Paper end
  }
 diff --git a/src/main/java/org/bukkit/command/defaults/PluginsCommand.java b/src/main/java/org/bukkit/command/defaults/PluginsCommand.java
-index b1d384e8..72c0c0bc 100644
+index d4e74d292..6cfd9f3c6 100644
 --- a/src/main/java/org/bukkit/command/defaults/PluginsCommand.java
 +++ b/src/main/java/org/bukkit/command/defaults/PluginsCommand.java
 @@ -0,0 +0,0 @@ public class PluginsCommand extends BukkitCommand {
@@ -42,7 +42,7 @@ index b1d384e8..72c0c0bc 100644
  
          StringBuilder pluginList = new StringBuilder();
 diff --git a/src/main/java/org/bukkit/plugin/java/JavaPluginLoader.java b/src/main/java/org/bukkit/plugin/java/JavaPluginLoader.java
-index c7782e7d..39f92d88 100644
+index 095448fe7..e91cb2c78 100644
 --- a/src/main/java/org/bukkit/plugin/java/JavaPluginLoader.java
 +++ b/src/main/java/org/bukkit/plugin/java/JavaPluginLoader.java
 @@ -0,0 +0,0 @@ public final class JavaPluginLoader implements PluginLoader {