Add link to gamerules class

Author: kennytv

src/content/posts/1.21.11.mdx

@@ -43,7 +43,7 @@ If your plugin is still using Spigot-mapped internal names (such as obfuscated c
 
 ### Gamerule changes
 
-Gamerules have been turned into a registry in Vanilla, so their names were changed from camelCase to snake_case and some gamerules merged or changes. The `GameRule` class still contains the old names for now, but you should replace their use.
+Gamerules have been turned into a registry in Vanilla, so their names were changed from camelCase to snake_case and some gamerules merged or changes. The `GameRule` class still contains the old names for now, but you should replace their use with [GameRules](https://jd.papermc.io/paper/1.21.11/org/bukkit/GameRules.html).
 
 ### Bed event changes