Correct types in "maths" expressions.

Author: Moderocky

src/main/java/org/byteskript/skript/lang/syntax/maths/AddExpression.java

@@ -46,7 +46,7 @@ public AddExpression() {
 
     @Override
     public Type getReturnType() {
-        return CommonTypes.NUMBER;
+        return CommonTypes.OBJECT;
     }
 
     @Override

src/main/java/org/byteskript/skript/lang/syntax/maths/MultiplyExpression.java

@@ -43,7 +43,7 @@ public MultiplyExpression() {
 
     @Override
     public Type getReturnType() {
-        return CommonTypes.NUMBER;
+        return CommonTypes.OBJECT;
     }
 
     @Override

src/main/java/org/byteskript/skript/lang/syntax/maths/SubtractExpression.java

@@ -42,7 +42,7 @@ public SubtractExpression() {
 
     @Override
     public Type getReturnType() {
-        return CommonTypes.NUMBER;
+        return CommonTypes.OBJECT;
     }
 
     @Override