cmd/govulncheck: update documentation for json flag

Make it point to the new Result data structure.

For golang/go#56042

Change-Id: I4eb1d319c958fef8adcb57adb20840e14f8ca3fa
Reviewed-on: https://go-review.googlesource.com/c/vuln/+/447675
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Run-TryBot: Zvonimir Pavlinovic <zpavlinovic@google.com>
diff --git a/cmd/govulncheck/doc.go b/cmd/govulncheck/doc.go
index c65e8cc..fdcbc5c 100644
--- a/cmd/govulncheck/doc.go
+++ b/cmd/govulncheck/doc.go
@@ -62,8 +62,8 @@
 when run on source. It has no effect when run on a binary.
 
 The -json flag causes govulncheck to print its output as a JSON object
-corresponding to the type [golang.org/x/vuln/vulncheck.Result]. The exit code
-of govulncheck is 0 when this flag is provided.
+corresponding to the type [golang.org/x/vuln/exp/govulncheck.Result]. The
+exit code of govulncheck is 0 when this flag is provided.
 
 The -tags flag accepts a comma-separated list of build tags to control which
 files should be included in loaded packages for source analysis.