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-Chunk-Inhabited-Time.patch

@@ -11,7 +11,7 @@ For people who want all chunks to be treated equally, you can chose a fixed valu
 This allows to fine-tune vanilla gameplay.
 
 diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
-index 2a71381d..bcf4dc52 100644
+index b910b648f..4afd7553d 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 {
@@ -30,7 +30,7 @@ index 2a71381d..bcf4dc52 100644
 +    }
  }
 diff --git a/src/main/java/net/minecraft/server/Chunk.java b/src/main/java/net/minecraft/server/Chunk.java
-index 591c823b..3d366dde 100644
+index 2dbfca3f0..85e17253d 100644
 --- a/src/main/java/net/minecraft/server/Chunk.java
 +++ b/src/main/java/net/minecraft/server/Chunk.java
 @@ -0,0 +0,0 @@ public class Chunk implements IChunkAccess {