Add a button next to the formatting buttons in a text cell to validate JSON objects in the cell

[walidsi]

Is your feature request related to a problem? Please describe.
No

Describe the solution you'd like
I wish Google Colab had a button next to the formatting buttons to validate a text cell containing only JSON.

Describe alternatives you've considered
I copy the json object, validate it in an external website, fix any errors, and then copy it back to the Colab cell.

Additional context