runtime.KeepAlive documentation code is incorrect

[efarrer]

Please answer these questions before submitting your issue. Thanks!

1. What version of Go are you using (go version)? 1.7

2. What operating system and processor architecture are you using (go env)? NA

3. What did you do? NA

4. What did you expect to see?
   The example code for the documentation/comment for runtime.KeepAlive has a typo. It should use the defined type "File", but the usage is mis-capitalized as "FILE".
   BAD: p := &FILE{d}
   GOOD: p := &File{d}

5. What did you see instead?

   p := &FILE{d}

The affected file is: src/runtime/mfinal.go

[gopherbot]

CL https://golang.org/cl/24830 mentions this issue.