Standardize beta feature labeling

[jyu00]

URL to the relevant guide or resource

https://quantum.cloud.ibm.com/docs/en/guides/fractional-gates https://quantum.cloud.ibm.com/docs/en/guides/stretch

Select all that apply

• [ ] new content request
• [ ] typo
• [ ] code bug
• [ ] out-of-date content
• [ ] broken link
• [x] other

Describe the fix or the content request.

As our services are becoming GA compliant, we should have a clear and consistent way of labeling beta features. For example, both fractional gates and stretch pages use experimental, and that mention is embedded in a paragraph and can easily be missed.

For new content requests - if the request is accepted, do you want to write the content?

I only want to review the material when it's finished