feat: unhide --oidc-redirect-url server option (#28072)

Unhides the `--oidc-redirect-url` / `CODER_OIDC_REDIRECT_URL` server
option so it appears in `coder server --help` and the deployment
configuration docs.

- Removed `Hidden: true` from the option in `codersdk/deployment.go`
- Regenerated CLI golden files and docs via `make gen`

---

> Generated with Coder Agents on behalf of @Emyrk

codersdk/deployment.go

@@ -3087,9 +3087,6 @@ communicating directly.`,
 			Value:      &c.OIDC.RedirectURL,
 			Group:      &deploymentGroupOIDC,
 			UseInstead: nil,
-			// In most deployments, this setting can only complicate and break OIDC.
-			// So hide it, and only surface it to the small number of users that need it.
-			Hidden: true,
 		},
 		{
 			Name: "OIDC Auto Repair Links",