feat: add docs about modmenu

Author: rootEnginear

README.md

@@ -2,7 +2,14 @@
 
 # Leaves Always Falling
 
-Make every leaf spawn leaf particles constantly, regardless of the season. Who doesn't love a dramatic effect?
+Make every leaf spawn leaf particles constantly, regardless of the season. — Who doesn't love a dramatic effect?
+
+You can also adjust the frequency of particle spawning with [ModMenu](https://github.com/Turnip-Labs/ModMenu)!
+
+1. Open the mod menu
+2. Select "Leaves Always Falling" mod from the left
+3. Click at ⚙️ icon on the right
+4. Adjust the "Leaves Falling Percentage" to the value you want (my personal favorite is 10%)
 
 > **Important**
 > Required [Babric](https://github.com/Turnip-Labs/babric-instance-repo/releases) to run the mod.