cmd/go/internal/modget: fix a typo introduced in CL 263267

Updates #37438

Change-Id: I78f377afd73dad75aed219836725a27fbaa5b69c
Reviewed-on: https://go-review.googlesource.com/c/go/+/268117
Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Dan Peterson <dpiddy@gmail.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>

Author: Bryan C. Mills

src/cmd/go/alldocs.go

@@ -89,8 +89,8 @@ downgrades the dependency. The version suffix @none indicates that the
 dependency should be removed entirely, downgrading or removing modules
 depending on it as needed.
 
-The version suffix @latest explicitly requests the latest minor release ofthe
-module named by the given path. The suffix @upgrade is like @latest but
+The version suffix @latest explicitly requests the latest minor release of
+the module named by the given path. The suffix @upgrade is like @latest but
 will not downgrade a module if it is already required at a revision or
 pre-release version newer than the latest released version. The suffix
 @patch requests the latest patch release: the latest released version