fix(docs): add codegen to aztec-builder command (#6098)

Missed the command in the original PR.

Also note that the `aztec-builder` is not automatically installed with
the sandbox, so for the command to work in the tutorial, devs will need
to install it with something like `npm i -g @aztec/builder` unless the
sandbox install command is updated.

docs/docs/developers/tutorials/token_portal/withdrawing_to_l1.md

@@ -84,7 +84,7 @@ You may get some unused variable warnings - you can ignore these.
 And generate the TypeScript interface for the contract and add it to the test dir. Run this inside `aztec-contracts/token_bridge`:
 
 ```bash
-aztec-builder target -o ../../src/test/fixtures
+aztec-builder codegen target -o ../../src/test/fixtures
 ```
 
 This will create a TS interface inside `fixtures` dir in our `src/test` folder!