[FR]: Document how to remove prefix for parametrized test

[kenoss]

Does the feature exist in the most recent commit?

Feature itself, yes. No documents.

Why do we need this feature?

https://chromium-review.googlesource.com/c/chromium/src/+/5040971/comment/c202d9b3_0ae8ff49/

In Chromium, lots of committers use "All" for instantiation name, even if multiple instances are not used. I think this is because they don't know how to opt-out it. Documentation is required.

Describe the proposal.

Document how to remove prefix for parametrized test

Is the feature specific to an operating system, compiler, or build system version?

N/A