Modified the way highlights are tested to allow for author to explicitly
mark the matches. Also added highlighting for fields and methods. Used
type checking in addition to ast to get better matching. Worked with
@stamblerre
Updates #34496
Change-Id: I462703e0011c4e0a4b98016e9c25af9bf1ead0b9
Reviewed-on: https://go-review.googlesource.com/c/tools/+/207899
Run-TryBot: Rohan Challa <rohan@golang.org>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>