Quickstart: switch .first() to .scalar() for querying single record

[carc1n0gen]

Quickstart doc should instruct to use .scalar() instead of .first() for single item queries.

With new query api .first() returns a Row object, not an instance of whatever model was queried, so it can't simply be passed to templates and used like Author.name, Post.title.

• fixes Quickstart doc should instruct to use .scalar() instead of .first() for single item queries #1115

Checklist:

• Add or update relevant docs, in the docs folder and in code.

[davidism]

Don't need a change entry for this, docs update as soon as they're merged.

[carc1n0gen]

Updated