Specify slot requirement is per level before someone asks

This is also part of 3.7.1

src/main/resources/assets/tconstruct/book/encyclopedia/en_us/abilities/interact/tconstruct_spitting.json

@@ -11,6 +11,6 @@
   "more_text_space": true,
   "effects": [
     "No max level",
-    "Requires 1 ability slot"
+    "Requires 1 ability slot per level"
   ]
 }