Updated Upstream (Bukkit/CraftBukkit) (#7604)

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

Bukkit Changes:
33a2b476 PR-734: Make PlayerInventory#getItem Nullable

CraftBukkit Changes:
953d3ddc SPIGOT-3034: PlayerKickEvent.setLeaveMessage(String) doesn't actually do anything
2c47af0c SPIGOT-6963: CraftMetaBlockState#getBlockState applied TileEntity ids without the minecraft namespace prefix.

patches/api/Fix-upstream-javadocs.patch

@@ -122,16 +122,3 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
      public Location getTo() {
          return to;
      }
-diff --git a/src/main/java/org/bukkit/inventory/PlayerInventory.java b/src/main/java/org/bukkit/inventory/PlayerInventory.java
-index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
---- a/src/main/java/org/bukkit/inventory/PlayerInventory.java
-+++ b/src/main/java/org/bukkit/inventory/PlayerInventory.java
-@@ -0,0 +0,0 @@ public interface PlayerInventory extends Inventory {
-      *
-      * @return the ItemStack in the given slot
-      */
--    @NotNull
-+    @Nullable
-     public ItemStack getItem(@NotNull EquipmentSlot slot);
- 
-     /**