fix copilot commit

Author: dpolasky

src/edu/umich/andykong/ptmshepherd/Mod.java

@@ -15,6 +15,8 @@ public String toString() {
 
     public boolean equals(Mod other) {
         return this.position == other.position && this.mass == other.mass;
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o)