doc: fix typo in Error.captureStackTrace

PR-URL: https://github.com/nodejs/node/pull/6811
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Roman Reiss <me@silverwind.io>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>

doc/api/errors.md

@@ -231,7 +231,7 @@ function MyError() {
 }
 
 // Without passing MyError to captureStackTrace, the MyError
-// frame would should up in the .stack property. by passing
+// frame would show up in the .stack property. By passing
 // the constructor, we omit that frame and all frames above it.
 new MyError().stack
 ```