Merge pull request #5718 from KLuuKer/patch-1

big.js.d.ts: use const enum instead of enum

big.js/big.js.d.ts

@@ -6,7 +6,7 @@
 
 declare module BigJsLibrary {
 
-    export enum RoundingMode {
+    export const enum RoundingMode {
         RoundTowardsZero = 0,
         RoundTowardsNearestAwayFromZero = 1,
         RoundTowardsNearestTowardsEven = 2,
@@ -200,4 +200,4 @@ declare module BigJsLibrary {
     }
 }
 
-declare var Big: BigJsLibrary.BigJS;
+declare var Big: BigJsLibrary.BigJS;