cmd/go: update alldocs.go

Ran go generate in order to update docs.

Change-Id: Ideb903427d153d0ff35e5164b7e79426b83b1afb
Reviewed-on: https://go-review.googlesource.com/111336Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/go/alldocs.go

@@ -697,9 +697,9 @@
 // a non-nil Error field; other information may or may not be missing
 // (zeroed).
 //
-// The -test flag causes list to add to its output test binaries for the
-// named packages that have tests, to make information about test
-// binary construction available to source code analysis tools.
+// The -test flag causes list to report not only the named packages
+// but also their test binaries (for packages with tests), to convey to
+// source code analysis tools exactly how test binaries are constructed.
 // The reported import path for a test binary is the import path of
 // the package followed by a ".test" suffix, as in "math/rand.test".
 // When building a test, it is sometimes necessary to rebuild certain