docs: fix some typos

What does this MR do?

Fixes typos in API documentation.

Are there points in the code the reviewer needs to double check?

No.

Why was this MR needed?

Types of returned objects are important in typed languages and the docs should be specific about the types of the fields it returns.

What are the relevant issue numbers?

N/A.

Screenshots (if relevant)

N/A

Does this MR meet the acceptance criteria?

Does this warrant a changelog entry?

• CHANGELOG entry added
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the style guides
• Branch has no merge conflicts with master (if you do - rebase it please)
• Squashed related commits together