Add reviewed example of duplicate API command

Author: RebeccaTamachiro

src/content/docs/secrets-store/manage-secrets/how-to.mdx

@@ -64,7 +64,16 @@ Duplicate a secret to keep the same secret value but change name, scope, or comm
 
 </TabItem> <TabItem label="API">
 
-[Add API instructions here]
+```bash
+curl https://api.cloudflare.com/client/v4/accounts/$ACCOUNT_ID/secrets_store/stores/$STORE_ID/secrets/$SECRET_ID/duplicate \
+--header "Authorization: Bearer $CLOUDFLARE_API_TOKEN" \
+--header "Content-Type: application/json" \
+--data '{
+    "name":"<NEW_DUPLICATE_NAME>",
+    "scopes":["workers"],
+    "comment":""
+}'
+```
 
 </TabItem> </Tabs>
 
@@ -97,7 +106,7 @@ https://api.cloudflare.com/client/v4/accounts/$ACCOUNT_ID/secrets_store/stores/$
     "comment":"<NEW_COMMENT>",
     "value":"<NEW_SECRET_VALUE>",
     "scopes":["workers"]
-	}'
+}'
 ```
 
 </TabItem> </Tabs>