"plaintext" instead of "cleartext" with docs/ops/integrations/prometheus/index.md

[dsbos]

The page says: "The control plane, gateway, and Envoy sidecar metrics will all be scraped over plaintext."

Shouldn't that "plaintext" be "cleartext"?

"Plain text" is text without formatting (e.g., plain text vs. HTML).

"Cleartext" is unencrypted data (as opposed to "ciphertext").

[NisheekaNynan1]

I'd like to work on this issue :) will get started unless there is any objection

[istio-policy-bot]

🚧 This issue or pull request has been closed due to not having had activity from an Istio team member since 2021-02-22. If you feel this issue or pull request deserves attention, please reopen the issue. Please see this wiki page for more information. Thank you for your contributions.

Created by the issue and PR lifecycle manager.