fixup! util/vizerror: add new package for visible errors

Signed-off-by: Will Norris <will@tailscale.com>

cmd/derper/depaware.txt

@@ -83,6 +83,7 @@ tailscale.com/cmd/derper dependencies: (generated by github.com/tailscale/depawa
         tailscale.com/util/mak                                       from tailscale.com/syncs
         tailscale.com/util/singleflight                              from tailscale.com/net/dnscache
         tailscale.com/util/strs                                      from tailscale.com/hostinfo+
+        tailscale.com/util/vizerror                                  from tailscale.com/tsweb
    W 💣 tailscale.com/util/winutil                                   from tailscale.com/hostinfo+
         tailscale.com/version                                        from tailscale.com/derp+
         tailscale.com/version/distro                                 from tailscale.com/hostinfo+

cmd/tailscaled/depaware.txt

@@ -305,6 +305,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/util/strs                                      from tailscale.com/hostinfo+
         tailscale.com/util/systemd                                   from tailscale.com/control/controlclient+
         tailscale.com/util/uniq                                      from tailscale.com/wgengine/magicsock+
+        tailscale.com/util/vizerror                                  from tailscale.com/tsweb
      💣 tailscale.com/util/winutil                                   from tailscale.com/control/controlclient+
         tailscale.com/version                                        from tailscale.com/derp+
         tailscale.com/version/distro                                 from tailscale.com/hostinfo+

tsweb/tsweb_test.go

@@ -186,7 +186,6 @@ func TestStdHandler(t *testing.T) {
 			},
 		},
 
-
 		{
 			name:     "handler returns generic error",
 			rh:       handlerErr(0, testErr),