_content/security/vuln: fix VS Code settings documentation

Update docs to use the preferred settings style for VS Code.

Fixes golang/go#61633

Change-Id: I2eb079bbc5a65a99330adcabe38b3bb315dc2402
Reviewed-on: https://go-review.googlesource.com/c/website/+/517776
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Suzy Mueller <suzmue@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

_content/security/vuln/editor.md

@@ -29,7 +29,7 @@ The [Go extension](https://marketplace.visualstudio.com/items?itemName=golang.go
 ```
 "go.diagnostic.vulncheck": "Imports", // enable the imports-based analysis by default.
 "gopls": {
-  "codelenses": {
+  "ui.codelenses": {
     "run_govulncheck": true  // "Run govulncheck" code lens on go.mod file.
   }
 }