#512: Expand Strider and Steerable entity API

By: Parker Hawke <hawkeboyz2@hotmail.com>

paper-api/src/main/java/org/bukkit/entity/Strider.java

@@ -3,4 +3,23 @@ package org.bukkit.entity;
 /**
  * Represents a Strider.
  */
-public interface Strider extends Animals, Vehicle { }
+public interface Strider extends Steerable, Vehicle {
+
+    /**
+     * Check whether or not this strider is out of warm blocks and shivering.
+     *
+     * @return true if shivering, false otherwise
+     */
+    public boolean isShivering();
+
+    /**
+     * Set whether or not this strider is shivering.
+     *
+     * Note that the shivering state is updated frequently on the server,
+     * therefore this method may not affect the entity for long enough to have a
+     * noticeable difference.
+     *
+     * @param shivering its new shivering state
+     */
+    public void setShivering(boolean shivering);
+}