Add option to make parrots stay on shoulders despite movement

Makes parrots not fall off whenever the player changes height, or touches water, or gets hit by a passing leaf.
Instead, switches the behavior so that players have to sneak to make the birds leave.

I suspect Mojang may switch to this behavior before full release.

To be converted into a Paper-API event at some point in the future?

== AT ==
public net.minecraft.world.entity.player.Player removeEntitiesOnShoulder()V

paper-server/patches/sources/net/minecraft/world/entity/player/Player.java.patch

@@ -80,7 +80,15 @@
              super.rideTick();
              this.oBob = this.bob;
              this.bob = 0.0F;
-@@ -719,7 +746,14 @@
+@@ -593,6 +620,7 @@
+         this.playShoulderEntityAmbientSound(this.getShoulderEntityLeft());
+         this.playShoulderEntityAmbientSound(this.getShoulderEntityRight());
+         if (!this.level().isClientSide && (this.fallDistance > 0.5F || this.isInWater()) || this.abilities.flying || this.isSleeping() || this.isInPowderSnow) {
++            if (!this.level().paperConfig().entities.behavior.parrotsAreUnaffectedByPlayerMovement) // Paper - Add option to make parrots stay
+             this.removeEntitiesOnShoulder();
+         }
+ 
+@@ -719,7 +747,14 @@
  
      @Nullable
      public ItemEntity drop(ItemStack stack, boolean throwRandomly, boolean retainOwnership) {
@@ -96,7 +104,7 @@
              this.swing(InteractionHand.MAIN_HAND);
          }
  
-@@ -809,7 +843,7 @@
+@@ -809,7 +844,7 @@
          }
  
          if (nbt.contains("LastDeathLocation", 10)) {
@@ -105,7 +113,7 @@
              Logger logger = Player.LOGGER;
  
              Objects.requireNonNull(logger);
-@@ -817,7 +851,7 @@
+@@ -817,7 +852,7 @@
          }
  
          if (nbt.contains("current_explosion_impact_pos", 9)) {
@@ -114,7 +122,7 @@
              Logger logger1 = Player.LOGGER;
  
              Objects.requireNonNull(logger1);
-@@ -854,7 +888,7 @@
+@@ -854,7 +889,7 @@
          }
  
          this.getLastDeathLocation().flatMap((globalpos) -> {
@@ -123,7 +131,7 @@
              Logger logger = Player.LOGGER;
  
              Objects.requireNonNull(logger);
-@@ -886,10 +920,10 @@
+@@ -886,10 +921,10 @@
              if (this.isDeadOrDying()) {
                  return false;
              } else {
@@ -136,7 +144,7 @@
                      }
  
                      if (world.getDifficulty() == Difficulty.EASY) {
-@@ -901,7 +935,13 @@
+@@ -901,7 +936,13 @@
                      }
                  }
  
@@ -151,7 +159,7 @@
              }
          }
      }
-@@ -923,10 +963,29 @@
+@@ -923,10 +964,29 @@
      }
  
      public boolean canHarmPlayer(Player player) {
@@ -184,7 +192,7 @@
      }
  
      @Override
-@@ -966,32 +1025,38 @@
+@@ -966,32 +1026,38 @@
          }
      }
  
@@ -237,7 +245,7 @@
      }
  
      public boolean isTextFilteringEnabled() {
-@@ -1144,10 +1209,15 @@
+@@ -1144,10 +1210,15 @@
  
                  f *= 0.2F + f2 * f2 * 0.8F;
                  f1 *= f2;
@@ -254,7 +262,7 @@
                      if (iprojectile.deflect(ProjectileDeflection.AIM_DEFLECT, this, this, true)) {
                          this.level().playSound((Player) null, this.getX(), this.getY(), this.getZ(), SoundEvents.PLAYER_ATTACK_NODAMAGE, this.getSoundSource());
                          return;
-@@ -1223,8 +1293,13 @@
+@@ -1223,8 +1294,13 @@
                                  if (entityliving2 != this && entityliving2 != target && !this.isAlliedTo((Entity) entityliving2) && (!(entityliving2 instanceof ArmorStand) || !((ArmorStand) entityliving2).isMarker()) && this.distanceToSqr((Entity) entityliving2) < 9.0D) {
                                      float f7 = this.getEnchantedDamage(entityliving2, f6, damagesource) * f2;
  
@@ -269,7 +277,7 @@
                                      Level world = this.level();
  
                                      if (world instanceof ServerLevel) {
-@@ -1240,9 +1315,26 @@
+@@ -1240,9 +1316,26 @@
                          }
  
                          if (target instanceof ServerPlayer && target.hurtMarked) {
@@ -296,7 +304,7 @@
                          }
  
                          if (flag2) {
-@@ -1308,9 +1400,14 @@
+@@ -1308,9 +1401,14 @@
                              }
                          }
  
@@ -312,7 +320,7 @@
                      }
                  }
  
-@@ -1351,7 +1448,14 @@
+@@ -1351,7 +1449,14 @@
  
      @Override
      public void remove(Entity.RemovalReason reason) {
@@ -328,7 +336,7 @@
          this.inventoryMenu.removed(this);
          if (this.containerMenu != null && this.hasContainerOpen()) {
              this.doCloseContainer();
-@@ -1391,7 +1495,13 @@
+@@ -1391,7 +1496,13 @@
      }
  
      public Either<Player.BedSleepingProblem, Unit> startSleepInBed(BlockPos pos) {
@@ -343,7 +351,7 @@
          this.sleepCounter = 0;
          return Either.right(Unit.INSTANCE);
      }
-@@ -1545,12 +1655,24 @@
+@@ -1545,12 +1656,24 @@
      }
  
      public void startFallFlying() {
@@ -369,7 +377,7 @@
      }
  
      @Override
-@@ -1665,10 +1787,21 @@
+@@ -1665,10 +1788,21 @@
          return this.experienceLevel >= 30 ? 112 + (this.experienceLevel - 30) * 9 : (this.experienceLevel >= 15 ? 37 + (this.experienceLevel - 15) * 5 : 7 + this.experienceLevel * 2);
      }
  
@@ -392,7 +400,7 @@
              }
  
          }
-@@ -1748,13 +1881,20 @@
+@@ -1748,13 +1882,20 @@
  
      @Override
      public void setItemSlot(EquipmentSlot slot, ItemStack stack) {
@@ -420,7 +428,7 @@
          }
  
      }
-@@ -1798,26 +1938,31 @@
+@@ -1798,26 +1939,31 @@
  
      public void removeEntitiesOnShoulder() {
          if (this.timeEntitySatOnShoulder + 20L < this.level().getGameTime()) {