cmd/go: update alldocs after CL 35150

Author of CL 35150 forgot to run mkalldocs.sh to update
the autogenerated alldocs.go

Change-Id: Ib824562db6044702456a221a8c6f9af412927a98
Reviewed-on: https://go-review.googlesource.com/35952Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/go/alldocs.go

@@ -17,7 +17,7 @@
 // 	clean       remove object files
 // 	doc         show documentation for package or symbol
 // 	env         print Go environment information
-// 	bug         print information for bug reports
+// 	bug         start a bug report
 // 	fix         run go tool fix on packages
 // 	fmt         run gofmt on package sources
 // 	generate    generate Go files by processing source
@@ -324,15 +324,14 @@
 // each named variable on its own line.
 //
 //
-// Print information for bug reports
+// Start a bug report
 //
 // Usage:
 //
 // 	go bug
 //
-// Bug prints information that helps file effective bug reports.
-//
-// Bugs may be reported at https://golang.org/issue/new.
+// Bug opens the default browser and starts a new bug report.
+// The report includes useful system information.
 //
 //
 // Run go tool fix on packages