trace: Make links in generated HTML be relative to the current path.

This will make it easier to serve /debug/requests off a different path.

This is groundwork towards addressing golang/go#12195.

Change-Id: If29a4c329609df1d5b09a3a88b8bdf1f8b622e49
Reviewed-on: https://go-review.googlesource.com/13824
Reviewed-by: Dave Day <djd@golang.org>
1 file changed