cmd/godoc: add redirect for x/term repo

Update golang/go#13104

Change-Id: I76102038d8dc87503c9a8994f9008b1a9fdb19d4
Reviewed-on: https://go-review.googlesource.com/17020
Reviewed-by: Dave Cheney <dave@cheney.net>

cmd/godoc/x.go

@@ -40,6 +40,7 @@ var xMap = map[string]xRepo{
 	"sync":       {"https://go.googlesource.com/sync", "git"},
 	"sys":        {"https://go.googlesource.com/sys", "git"},
 	"talks":      {"https://go.googlesource.com/talks", "git"},
+	"term":       {"https://go.googlesource.com/term", "git"},
 	"text":       {"https://go.googlesource.com/text", "git"},
 	"time":       {"https://go.googlesource.com/time", "git"},
 	"tools":      {"https://go.googlesource.com/tools", "git"},