Improve clarity of ‘Objects are not valid as a React child’ error message. Closed #34530

[ShivrajShelar99]

Motivation

The current error message: Objects are not valid as a React child (found: [object Object])

It can be confusing for beginners. It does not provide guidance on how to fix the issue or link to relevant documentation.

This PR improves clarity by:

• Displaying object keys when possible.
• Suggesting JSON.stringify(obj) or mapping over arrays.
• Providing more actionable guidance for developers.

How I Tested This Change:

• Clone the repository, switch to your branch, and install all necessary dependencies.
• Build React in development mode to ensure the changes take effect.
• Create a test application and render an object or array in JSX to reproduce the original error.
• Run the test app and verify that the new error message displays object keys, suggests using JSON.stringify(obj) or mapping over arrays, and provides clear actionable guidance.

[ShivrajShelar99]

Updated the React error message for invalid children to be more descriptive.
Now suggests using an array for collections or converting objects with JSON.stringify(obj) and rendering properties explicitly.
Includes a reference link to the React docs for rendering lists for better guidance.
Closes #34530