Merge pull request #1039 from realies/patch-1

make `client` const instead of variable

src/collections/_documentation/error-reporting/configuration/drain-example/javascript.md

@@ -3,7 +3,7 @@ waits and will return a promise that resolves when everything was flushed or the
 in.
 
 ```javascript
-let client = Sentry.getCurrentHub().getClient();
+const client = Sentry.getCurrentHub().getClient();
 if (client) {
   client.close(2000).then(function() {
     process.exit();