fix(docs): Standardising the use of strawberry_django throughout the documentation.

[ArcD7]

Replaced strawberry.django withstrawberry_django where ever possible with the necessary imports for the same, thereby standardising the use of strawberry_django throughout the documentation.

Description

Types of Changes

• [ ] Core
• [ ] Bugfix
• [ ] New feature
• [ ] Enhancement/optimization
• [x] Documentation

Issues Fixed or Closed by This PR

• fix #434

Checklist

• [ ] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [x] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes.
• [ ] I have tested the changes and verified that they work and don't break anything (as well as I can manage).