update readme

readme.md

@@ -3,4 +3,4 @@ This is a filter for the World of Warcraft addon [BetterBags](https://github.com
 
 The plugin was written for Classic SoD so it might not work for other versions of the game.
 
-It will collect all items assigned to an ItemRack set and place them in a single category. Might add the option to split them up into seperate categories for each set later but no promises.
+It will collect all items assigned to an ItemRack set and place them in a single category. Might add the option to split them up into separate categories for each set later but no promises.