Invalid Flutter Documentation links

[FabianUntermoser]

There are some links to the Flutter documentation, which do not work. Examples:

• https://docs.flutter.io/flutter/material/Icons-class.html
• https://docs.flutter.io/flutter/widgets/Icon-class.html

They should be replaced with the correct links:

• https://api.flutter.dev/flutter/material/Icons-class.html
• https://api.flutter.dev/flutter/widgets/Icon-class.html

[guidezpl]

Hi, can you please link the pages with the invalid links?

[guidezpl]

Found them, fixed soon.