Updated Upstream (Paper & Airplane)

Upstream has released updates that appear to apply and compile correctly

Paper Changes:
47d48790d Change return type of ItemStack#editMeta to allow checking for successful vs non-successful edits
7aabe7d56 [CI-SKIP] fix minecart vs minecraft typos (#5713)
f775e87b4 [CI-SKIP] ci: update setup-java action (#5710)
c58b3b277 ci: replace Java 11 with Java 16 in GH Actions build flow (#5709)
4b72327a6 ItemStack#editMeta
68984b664 Add Unix domain socket support (#5611)
68c67e680 Add Mob#lookAt API (#5633)
4bacecd16 [Auto] Updated Upstream (Bukkit/CraftBukkit)
1f28e6eeb Fix default ChatRenderer when no plugins are installed (#5702)
ecb0d32ca Enhance (Async)ChatEvent with per-viewer rendering API (#5684)

Airplane Changes:
636dbff0f [ci skip] Cleanup mcdev import files
c57932048 [ci skip] Remove icons
7ada9a476 [skip ci] Need to specify 1.16.5 in the README of course
813df1a44 Update README
daf3f0b29 Optimize air case for raytracing

patches/api/0019-ItemStack-convenience-methods.patch

@@ -50,7 +50,7 @@ index 9b1c9e60dba9ea3ef8d8e164f13dd76daf57db8e..b04e9de7183f00a9a47c1fce26895c83
 +    // Purpur end
  }
 diff --git a/src/main/java/org/bukkit/inventory/ItemStack.java b/src/main/java/org/bukkit/inventory/ItemStack.java
-index 0f8c593ae9bca46081f0b22c2d763a2699175398..ff17e3165beedee235c738ebc8e9c9f1a7ab52ca 100644
+index 3e2c08641edffcf00b230ad624685aaff30af0e5..fceba6780a15c274c4689eccbeb6dfb2eee25ed9 100644
 --- a/src/main/java/org/bukkit/inventory/ItemStack.java
 +++ b/src/main/java/org/bukkit/inventory/ItemStack.java
 @@ -17,6 +17,18 @@ import org.bukkit.inventory.meta.ItemMeta;
@@ -72,7 +72,7 @@ index 0f8c593ae9bca46081f0b22c2d763a2699175398..ff17e3165beedee235c738ebc8e9c9f1
  
  /**
   * Represents a stack of items.
-@@ -896,4 +908,626 @@ public class ItemStack implements Cloneable, ConfigurationSerializable, net.kyor
+@@ -914,4 +926,626 @@ public class ItemStack implements Cloneable, ConfigurationSerializable, net.kyor
          return Bukkit.getUnsafe().isValidRepairItemStack(toBeRepaired, this);
      }
      // Paper end