Fix starlette example for 'running reactpy' docs

[dridk]

Current Situation

From here : https://reactpy.dev/docs/guides/getting-started/running-reactpy.html
Code example doesn't work . Backend import are missing.

from reactpy import component, html
from reactpy.backend.starlette import configure

# ==> missing : import Starlete

@component
def HelloWorld():
    return html.h1("Hello, world!")


app = Starlette()
configure(app, HelloWorld)

Proposed Actions

Try do fix it myself. But the doc example from the repository seems ok.