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/Configurable-sprint-interruption-on-attack.patch

@@ -6,7 +6,7 @@ Subject: [PATCH] Configurable sprint interruption on attack
 If the sprint interruption is disabled players continue sprinting when they attack entities.
 
 diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
-index 94ffba97b..0b6e812d8 100644
+index b87133fcf..c57f7e7e8 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 {
@@ -20,7 +20,7 @@ index 94ffba97b..0b6e812d8 100644
 +    }
  }
 diff --git a/src/main/java/net/minecraft/server/EntityHuman.java b/src/main/java/net/minecraft/server/EntityHuman.java
-index 8b35443bd..dfd004f02 100644
+index 9df182def..ec99fb62b 100644
 --- a/src/main/java/net/minecraft/server/EntityHuman.java
 +++ b/src/main/java/net/minecraft/server/EntityHuman.java
 @@ -0,0 +0,0 @@ public abstract class EntityHuman extends EntityLiving {