docs: de-emphasize InferSchemaType<> in TypeScript docs in favor of automatic inference

[vkarpov15]

Re: #14286

Summary

Did a bunch of work on the TypeScript docs to make it more clear that using InferSchemaType<> is usually not necessary. Because InferSchemaType<> returns a mostly raw document interface but with DocumentArrays and Subdocs, it typically isn't useful for end users because you end up with a mostly-lean document. InferSchemaType<> is still useful internally because it helps automatic type inference internally, but it unfortunately tries to satisfy both the lean document type and the hydrated document type, which leads to confusion.

For user-facing API, we should instead encourage inferRawDocType from #13900, which will infer the raw doc type from the schema, and inferHydratedDocumentType, which will infer the fully hydrated document type but is not yet written.

Examples

[hasezoey]

Looks good, some suggestions if we touch that documentation