Fix ft documentation in "from example" guide.

[erikgaas]

The current tutorial for ft tags says output can be

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def __ft__(self):
        return ['div', [f'{self.name} is {self.age} years old.'], {}]

p = Person('Jonathan', 28)
print(to_xml(Div(p, "more text", cls="container")))

Notice the list being returned by ft. I think this is not valid, so this is fixed in the docs.

Addresses confusion in #775

[gitnotebooks]

Found 1 changed notebook. Review the changes at https://app.gitnotebooks.com/AnswerDotAI/fasthtml/pull/806