fix tx building example code

Author: arobsn

docs/.vitepress/config.ts

@@ -36,7 +36,7 @@ function nav(): DefaultTheme.NavItem[] {
       items: [
         {
           text: "Fleet SDK",
-          link: "https://github.com/fleet-sdk/fleet/blob/master/CONTRIBUTING.md",
+          link: "https://github.com/fleet-sdk/fleet/blob/master/CONTRIBUTING.md"
         },
         {
           text: "Documentation",

docs/wallet-interaction.md

@@ -222,7 +222,7 @@ const unsignedTransaction = new TransactionBuilder(creationHeight)
   .sendChangeTo(changeAddress)
   .payMinFee()
   .build()
-  .toPlainObject();
+  .toEIP12Object();
 
 const signedTransaction = await ergo.sign_tx(unsignedTransaction); // [!code focus]
 ```