doc: specify which pprof version was vendored in go1.10

Change-Id: I248cb10a2e24f089600c13e86da251970c773d95
Reviewed-on: https://go-review.googlesource.com/87662Reviewed-by: Ian Lance Taylor <iant@golang.org>

doc/go1.10.html

@@ -370,8 +370,9 @@ without the binary that produced the profile.
 </p>
 
 <p>
-The <a href="/cmd/pprof/"><code>go</code>&nbsp;<code>tool</code>&nbsp;<code>pprof</code></a> profile visualizer has been updated to
-the latest version from <a href="https://github.com/google/pprof">github.com/google/pprof</a>,
+The <a href="/cmd/pprof/"><code>go</code>&nbsp;<code>tool</code>&nbsp;<code>pprof</code></a>
+profile visualizer has been updated to git version 9e20b5b (2017-11-08)
+from <a href="https://github.com/google/pprof">github.com/google/pprof</a>,
 which includes an updated web interface.
 </p>