Add entity heal API (#10267)

patches/api/Missing-Entity-API.patch

@@ -12,6 +12,7 @@ Co-authored-by: Amin <amin.haddou@frg.wwschool.de>
 Co-authored-by: TrollyLoki <trollyloki@gmail.com>
 Co-authored-by: FireInstall <kettnerl@hu-berlin.de>
 Co-authored-by: maxcom1 <46265094+maxcom1@users.noreply.github.com>
+Co-authored-by: TotalledZebra <Holappa57@gmail.com>
 
 diff --git a/src/main/java/io/papermc/paper/entity/SchoolableFish.java b/src/main/java/io/papermc/paper/entity/SchoolableFish.java
 new file mode 100644
@@ -348,6 +349,36 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
   */
 -public interface Cod extends Fish { }
 +public interface Cod extends io.papermc.paper.entity.SchoolableFish { } // Paper - Schooling Fish API
+diff --git a/src/main/java/org/bukkit/entity/Damageable.java b/src/main/java/org/bukkit/entity/Damageable.java
+index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
+--- a/src/main/java/org/bukkit/entity/Damageable.java
++++ b/src/main/java/org/bukkit/entity/Damageable.java
+@@ -0,0 +0,0 @@ public interface Damageable extends Entity {
+      */
+     void setHealth(double health);
+ 
++    // Paper start - entity heal API
++    /**
++     * Heal this entity by the given amount. This will call {@link org.bukkit.event.entity.EntityRegainHealthEvent}.
++     *
++     * @param amount heal amount
++     */
++    default void heal(final double amount) {
++        this.heal(amount, org.bukkit.event.entity.EntityRegainHealthEvent.RegainReason.CUSTOM);
++    }
++
++    /**
++     * Heal this entity by the given amount. This will call {@link org.bukkit.event.entity.EntityRegainHealthEvent}.
++     *
++     * @param amount heal amount
++     * @param reason heal reason
++     */
++    void heal(double amount, @NotNull org.bukkit.event.entity.EntityRegainHealthEvent.RegainReason reason);
++    // Paper end - entity heal API
++
+     /**
+      * Gets the entity's absorption amount.
+      *
 diff --git a/src/main/java/org/bukkit/entity/Enderman.java b/src/main/java/org/bukkit/entity/Enderman.java
 index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
 --- a/src/main/java/org/bukkit/entity/Enderman.java

patches/server/Missing-Entity-API.patch

@@ -42,6 +42,7 @@ Co-authored-by: Amin <amin.haddou@frg.wwschool.de>
 Co-authored-by: TrollyLoki <trollyloki@gmail.com>
 Co-authored-by: FireInstall <kettnerl@hu-berlin.de>
 Co-authored-by: maxcom1 <46265094+maxcom1@users.noreply.github.com>
+Co-authored-by: TotalledZebra <Holappa57@gmail.com>
 
 diff --git a/src/main/java/com/destroystokyo/paper/entity/ai/MobGoalHelper.java b/src/main/java/com/destroystokyo/paper/entity/ai/MobGoalHelper.java
 index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
@@ -632,6 +633,24 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +    }
 +    // Paper end - Missing Dolphin API
  }
+diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftEnderDragonPart.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftEnderDragonPart.java
+index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
+--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftEnderDragonPart.java
++++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftEnderDragonPart.java
+@@ -0,0 +0,0 @@ public class CraftEnderDragonPart extends CraftComplexPart implements EnderDrago
+         this.getParent().setHealth(health);
+     }
+ 
++    // Paper start - entity heal API
++    @Override
++    public void heal(final double amount, final org.bukkit.event.entity.EntityRegainHealthEvent.RegainReason reason) {
++        this.getParent().heal(amount, reason);
++    }
++    // Paper end - entity heal API
++
+     @Override
+     public double getAbsorptionAmount() {
+         return this.getParent().getAbsorptionAmount();
 diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftEnderman.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftEnderman.java
 index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
 --- a/src/main/java/org/bukkit/craftbukkit/entity/CraftEnderman.java
@@ -832,6 +851,20 @@ diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
 index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
 --- a/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
 +++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
+@@ -0,0 +0,0 @@ public class CraftLivingEntity extends CraftEntity implements LivingEntity {
+         }
+     }
+ 
++    // Paper start - entity heal API
++    @Override
++    public void heal(final double amount, final org.bukkit.event.entity.EntityRegainHealthEvent.RegainReason reason) {
++        this.getHandle().heal((float) amount, reason);
++    }
++    // Paper end - entity heal API
++
+     @Override
+     public double getAbsorptionAmount() {
+         return this.getHandle().getAbsorptionAmount();
 @@ -0,0 +0,0 @@ public class CraftLivingEntity extends CraftEntity implements LivingEntity {
  
      @Override