Fix Bug in ast.lua

Author: levno-710

src/prometheus/ast.lua

@@ -88,7 +88,7 @@ local astKindExpressionLookup = {
 	[AstKind.SubExpression] = 8;
 	[AstKind.MulExpression] = 7;
 	[AstKind.DivExpression] = 7;
-	[AstKind.ModExpression] = 6;
+	[AstKind.ModExpression] = 7;
 	[AstKind.NotExpression] = 5;
 	[AstKind.LenExpression] = 5;
 	[AstKind.NegateExpression] = 5;