message: docs(quick-start-guide): fix "an" -> "a"
diff: @@ -99,8 +99,8 @@ class User {
  Like `public: string[]` is in reflection only `Array`.
  :::
  -[Look here for what `!` means on an property](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-0.html#non-null-assertion-operator)
  -[Look here for what `?` means on an property](https://www.typescriptlang.org/docs/handbook/functions.html#optional-and-default-parameters)
  +[Look here for what `!` means on a property](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-0.html#non-null-assertion-operator)
  +[Look here for what `?` means on a property](https://www.typescriptlang.org/docs/handbook/functions.html#optional-and-default-parameters)
  ## How to Start using typegoose
  