blog: update to latest x/tools for Markdown <pre> fix

This fixes <pre> blocks containing blank lines, like in
https://blog.golang.org/v2-go-modules.

Fixes golang/go#37972.

Change-Id: I44adf6ae72f600e19c995a1fde36537d4f06008f
Reviewed-on: https://go-review.googlesource.com/c/blog/+/224943
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

go.mod

@@ -6,7 +6,7 @@ require (
 	github.com/gorilla/context v1.1.1
 	golang.org/x/net v0.0.0-20200226121028-0de0cce0169b
 	golang.org/x/text v0.3.2
-	golang.org/x/tools v0.0.0-20200318150045-ba25ddc85566
+	golang.org/x/tools v0.0.0-20200323171731-e609210bcd3f
 	golang.org/x/website v0.0.0-20190903192346-00e97558e113
 	gopkg.in/tomb.v2 v2.0.0-20161208151619-d5d1b5820637
 )

go.sum

@@ -74,8 +74,8 @@ golang.org/x/tools v0.0.0-20190506145303-2d16b83fe98c/go.mod h1:RgjU9mgBXZiqYHBn
 golang.org/x/tools v0.0.0-20190516015132-d1a3278ee749 h1:L1RW4r06KGFktOvNizsWNBWHn4V2I/p9SNRLhNn6hzM=
 golang.org/x/tools v0.0.0-20190516015132-d1a3278ee749/go.mod h1:RgjU9mgBXZiqYHBnxXauZ1Gv1EHHAz9KjViQ78xBX0Q=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
-golang.org/x/tools v0.0.0-20200318150045-ba25ddc85566 h1:OXjomkWHhzUx4+HldlJ2TsMxJdWgEo5CTtspD1wdhdk=
-golang.org/x/tools v0.0.0-20200318150045-ba25ddc85566/go.mod h1:Sl4aGygMT6LrqrWclx+PTx3U+LnKx/seiNR+3G19Ar8=
+golang.org/x/tools v0.0.0-20200323171731-e609210bcd3f h1:dlzvbS5gAya85bCBRskGDmUQ27VayugwRFHdr4dy3dU=
+golang.org/x/tools v0.0.0-20200323171731-e609210bcd3f/go.mod h1:Sl4aGygMT6LrqrWclx+PTx3U+LnKx/seiNR+3G19Ar8=
 golang.org/x/website v0.0.0-20190903192346-00e97558e113 h1:uwiB8M+mk9E2X0p+Pr1KlfnA1eWSheaeYkVmsesWLKg=
 golang.org/x/website v0.0.0-20190903192346-00e97558e113/go.mod h1:xGSACM0vBhAtMi/g1gCnV3jnZ7fON45PUeLicIqMMQo=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=