HOLI-5486: add comment to radius

app/api_types.ts

@@ -38,5 +38,5 @@ export enum ApiRoutes {
 export enum ApiDefaults {
   CITY = "ALL_CITIES",
   MIN_RADIUS = 5,
-  MAX_RADIUS = 50,
+  MAX_RADIUS = 50, // The largest radius in kilometers that the Voltastics API is capable of handling.
 }