cmd/go: fuzz docs should update TB doc to say “T, B, and F.”

[rsc]

% gotip doc testing.TB
...
    TB is the interface common to T and B.

should say “T, B, and F.”

/cc @golang/fuzzing

[toothrot]

Checking in on this issue as it's labeled a release blocker for Go 1.18. Is there any update?

[toothrot]

@golang/fuzzing Friendly ping that this issue is marked as a release-blocker for Go 1.18.

[gopherbot]

Change https://golang.org/cl/365894 mentions this issue: testing: fix the documentation comment for testing.TB interface

[uppalabharath]

@cherrymui , @julieqiu

I gave a try to fix this issue. I made the changes and raised a Gerrit review.
But I need help in testing these changes. Is there a guide that I can follow to test out the fix.

Thanks