A simple PR that adds enforcing onto schema

[ShadiestGoat]

Summary
With this, when creating a new schema using typescript, you get enforcing for built in types. Solves issue #9946. I know I mentioned I wouldn't create a PR but I kinda got impatient aha.
It's really annoying to not have auto complete on IDEs when writing strings, but with this bad boy of a PR, it prioritizes the built in types, so this way SchemaDefinition<T> doesn't affect anything

Examples

interface IUser {
   username: string,
   password: string,
   age: number
}
//old
new Schema<IUser & Document, Model<IUser & Document>, IUser>({
      username: "adjasd",
      password: "sad",
      age: "jkd"
})
// no errors, no auto complete :O

//new
new Schema<IUser & Document, Model<IUser & Document>, IUser>({
      username: "adjasd",
      password: "sad",
      age: "jkd"
})
//big time errors because adjasd and sad isn't "String" | "string", and jkd isnt "Number" | "number", autocomplete!

[ShadiestGoat]

Uhh the checks aren't relevant to the PR.

[vkarpov15]

Nice, this is very clever. Thanks 👍