Site-www: Typo in "Understanding null safety"

[AlexV525]

In our translation of this doc we found some typos. Some of them has been fixed already, but this one is still remained:

https://github.com/dart-lang/site-www/blob/4ef930c2feaaf49d614d63aba91c6d420f7b0750/src/null-safety/understanding-null-safety/index.md#L713

Should the now non-nullable be the new non-nullable ?

[kwalrath]

Pretty sure @munificent meant "now". List used to be nullable, but "now" (i.e. under null safety) it's non-nullable.

[AlexV525]

Thanks for the explanation!