L3-Chains cell 33, 34, 35 fail

Modify template as below:
DEFAULT to default
missing ``` after json

MULTI_PROMPT_ROUTER_TEMPLATE =
(…)

{{{{
    "destination": string \ name of the prompt to use or "default"
    "next_inputs": string \ a potentially modified version of the original input
}}}}

REMEMBER: “destination” MUST be one of the candidate prompt
names specified below OR it can be “default” if the input is not
well suited for any of the candidate prompts.
REMEMBER: “next_inputs” can just be the original input
if you don’t think any modifications are needed.
(…)
<< OUTPUT (remember to include the ```json```)>>"""