[Docs] Add proper factory definition in example (#1688)

* Fix: Bump minimum required Ruby in gemspec (Earlopain).

* Fix: Broken link in `FactoryBot.modify` docs (Matt Brictson).
* Fix: Broken link in `FactoryBot.lint` docs (Anton Dieterle).

6.4.5

* Changed: Support Ruby 3.0+, Rails 6.1+ (Mike Burns).

6.4.4

* Internal: Remove observer dependency (Earlopain).

6.4.3

* Fix: Support models without ID setters in build_stubbed (Olivier Bellone).
* Fix: Explicit observer dependency (Oleg Antonyan).
* Internal: Add Rails 7.1 to CI (Olivier Bellone).
* Internal: Bump github actions/checkout to v4 (Lorenzo Zabot)
* Internal: Stop passing disable-error_highlight in CI (Mike Burns).
* Internal: Relax the exception message check (Mike Burns).

Version 6.4.2

* Fix: top-level traits pass their class to ActiveSupport::Notifications
  (makicamel).

Version 6.4.1

* Fix: factories with traits pass their class to ActiveSupport::Notifications
  (makicamel).

Version 6.4.0

* Added: if `build_stubbed` detects a UUID primary key, generate the correct
  type (Peter Boling, Alexandre Ruban).
* Docs: show examples of Ruby 3 syntactic sugars (Sean Doyle).
* Internal: resolve test warning messages (Mike Burns).

Version 6.3.0

* Fix: link to changelog for RubyGems (Berkan Ünal).
* Fix: integrate with Ruby 3.2's `did_you_mean` library (Daniel Colson).
* Changed: explicitly define `#destroyed?` within the `Stub` strategy to return `false` to be consistent
  with ActiveRecord (Benjamin Fleischer).
* Added: announce `factory_bot.compile_factory` notification (Sean Doyle).
* Docs: clarify that custom strategies need to define `#to_sym` (Edmund Korley, Jonas S).
* Docs: fix CI link in README (Mark Huk).
* Docs: fix GitHub links (Robert Fletcher).
* Docs: install this library with `bundle add` (Glauco Custódio).
* Docs: re-write into mdBook (Mike Burns, Sara Jackson, Stefanni Brasil)
* Docs: clarify that automatic trait definitions could introduce new linting errors (Lawrence Chou).
* Internal: skip TruffleRuby on Rails 5.0, 5.1, 5.2 (Andrii Konchyn).
* Internal: fix typoes throughout codebase (Yudai Takada).
* Internal: run CI on `actions/checkout` v3 (Yudai Takada).
* Internal: follow standardrb code style (Yudai Takada).
* Internal: stop using Hound (Daniel Nolan).
* Internal: only run simplecov on C Ruby (Daniel Colson).
* Internal: quieter Cucumber (Daniel Colson).
* Internal: Ruby 3.2 support (Daniel Colson).
* Internal: Mike Burns is the CODEOWNER (Stefanni Brasil).

v6.2.1

* Added: CI testing against truffleruby
* Changed: Documentation improvements for sequences and traits
* Fixed: ActiveSupport::Notifications reporting strategy through associations now report as symbols
* Fixed: `add_attribute` with reserved keywords assigns values correctly