Remove django-hstore and django-rest-framework-hstore from 3rd party serializers documentation page (#9860)

Both are unmaintained for many years and we have builtin HStoreField.

Author: felixxm

docs/api-guide/fields.md

@@ -849,10 +849,6 @@ the [djangorestframework-recursive][djangorestframework-recursive] package provi
 
 The [django-rest-framework-gis][django-rest-framework-gis] package provides geographic addons for django rest framework like a `GeometryField` field and a GeoJSON serializer.
 
-## django-rest-framework-hstore
-
-The [django-rest-framework-hstore][django-rest-framework-hstore] package provides an `HStoreField` to support [django-hstore][django-hstore] `DictionaryField` model field.
-
 [cite]: https://docs.djangoproject.com/en/stable/ref/forms/api/#django.forms.Form.cleaned_data
 [html-and-forms]: ../topics/html-and-forms.md
 [FILE_UPLOAD_HANDLERS]: https://docs.djangoproject.com/en/stable/ref/settings/#std:setting-FILE_UPLOAD_HANDLERS
@@ -862,8 +858,6 @@ The [django-rest-framework-hstore][django-rest-framework-hstore] package provide
 [drf-extra-fields]: https://github.com/Hipo/drf-extra-fields
 [djangorestframework-recursive]: https://github.com/heywbj/django-rest-framework-recursive
 [django-rest-framework-gis]: https://github.com/djangonauts/django-rest-framework-gis
-[django-rest-framework-hstore]: https://github.com/djangonauts/django-rest-framework-hstore
-[django-hstore]: https://github.com/djangonauts/django-hstore
 [python-decimal-rounding-modes]: https://docs.python.org/3/library/decimal.html#rounding-modes
 [django-current-timezone]: https://docs.djangoproject.com/en/stable/topics/i18n/timezones/#default-time-zone-and-current-time-zone
 [django-docs-select-related]: https://docs.djangoproject.com/en/stable/ref/models/querysets/#django.db.models.query.QuerySet.select_related