Add more information and examples about secret-files

[akbergsn]

Is this a docs issue?

• [x] My issue is about the documentation content or website

Type of issue

Other

Description

I used this page often, but I was struggling to get the docker action to do what I was doing locally. I was unaware of exactly how to use secret-files the same way the documentation showed for multi-line well-formatted files specifically for Rust. I stumbled upon this link to someone who got it working and I believe this can be added to the documentation and it will help many more people use secret-file. Thanks! https://github.com/docker/build-push-action/issues/293

Location

https://docs.docker.com/build/building/secrets/

Suggestion

Add some information from the people who worked to close the issue with secret-files to the documentation.