Rename baby zombie movement config option

This option does not set the absolute speed of the entity as the name
implies. It sets a modifier. The default (vanilla) value of `0.5` sets
the baby zombie to move at 50% faster than the base speed.

A negative value like `-0.4` would set them to move at 40% slower.

There should be no functional changes as a result of this change, it's
just clarifying the config name.

Spigot-Server-Patches/Disable-explosion-knockback.patch

@@ -5,7 +5,7 @@ Subject: [PATCH] Disable explosion knockback
 
 
 diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
-index a5ec0bc0e0..6a307d5dd6 100644
+index 131b78dec..3fa78d286 100644
 --- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
 +++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
 @@ -0,0 +0,0 @@ public class PaperWorldConfig {
@@ -19,7 +19,7 @@ index a5ec0bc0e0..6a307d5dd6 100644
 +    }
  }
 diff --git a/src/main/java/net/minecraft/server/EntityLiving.java b/src/main/java/net/minecraft/server/EntityLiving.java
-index 678dae6dae..061f708aea 100644
+index 47379046d..fd5d1e1c8 100644
 --- a/src/main/java/net/minecraft/server/EntityLiving.java
 +++ b/src/main/java/net/minecraft/server/EntityLiving.java
 @@ -0,0 +0,0 @@ public abstract class EntityLiving extends Entity {
@@ -48,7 +48,7 @@ index 678dae6dae..061f708aea 100644
                  if (!this.f(damagesource)) {
                      SoundEffect soundeffect = this.getSoundDeath();
 diff --git a/src/main/java/net/minecraft/server/Explosion.java b/src/main/java/net/minecraft/server/Explosion.java
-index bcff117619..6eeff4ce59 100644
+index bd6a0bd16..8cfdac036 100644
 --- a/src/main/java/net/minecraft/server/Explosion.java
 +++ b/src/main/java/net/minecraft/server/Explosion.java
 @@ -0,0 +0,0 @@ public class Explosion {