doc: NGINX reverse proxy -- reportedly difficult to read

[mjang]

Describe the bug

Doc in question: https://docs.nginx.com/nginx/admin-guide/web-server/reverse-proxy/

Reported through Qualtrics survey

Confirmation

• Measured readability with Flesch-Kincaid. Reading level: 10.34
• Sentences longer than 28 words: 9

Expected behavior

Readable content, especially for users for whom English is a second language

[mjang]

Note: @travisamartin has WiP to ID more "difficult to read" content. Candidate: https://docs.nginx.com/nginx/admin-guide/security-controls/securing-http-traffic-upstream/

Per test using vale, grade level of that doc is 12.33

[noxian-byte]

Hello @mjang

I'd like to give it a go.I will start working on it and submit a PR soon.