Minor changes to the API documentation

[Siva-7482]

Summary

We have identified minor improvements in The Things Stack API documentation.

1. Update the length of token-id and token-secret.
2. Update the typo of the word perform.
3. Update the URL references of messages.proto and lorawan.proto.
4. Update The Things Stack Community Edition as The Things Stack Sandbox.

Why do we need this ?

To ensure the API documentation is up to date.

What is already there? What do you see now?

The Things Stack API documentation

What is missing? What do you want to see?

Update the API documentation for the recommended sections.

How do you propose to document this?

1. Update the length of token-id, and token-secret:

In the 'What are API Keys?' section, it is noted that there is a discrepancy in the length of the API Keys.

The token-id length is mentioned as 24 characters, but it seems 39 characters long. Similarly, the token-secret length is mentioned as 32 characters, whereas it seems 52 characters in length.

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2. Update the typo of the word perform:

The Authorization section contains a typo; perfrom should be corrected to perform. Please find the section here: Authorization Section

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3. Update the URL references of messages.proto and lorawan.proto:

The URLs for messages.proto and lorawan.proto are broken, resulting in a 404 Not Found error when accessed. Please update the messages.proto and lorawan.proto with the correct URLs. Ref: LoRa Gateway MQTT

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4. Update The Things Stack Community Edition as The Things Stack Sandbox:

In the errors section of the API documentation, we need to update The Things Stack Community Edition with The Things Stack Sandbox. Please find the reference here: Troubleshooting

Can you do this yourself and submit a Pull Request?

We do not have the references for the messages.proto and lorawan.proto. Hence, filed this issue instead of PR.

No, @nejraselimovic

[KrishnaIyer]

Covered in #1308
Next time @Siva-7482 please create a PR since you have all the required information.