constants library Null safety

Constants

kAnalyticsKey → const String
'ga_ad'
kDarkMode → const String
'dark'
kDartPadHost → const String
'dartpad.dev'
kLightMode → const String
'light'
kNullSafetyKey → const String
'null_safety'
kRunKey → const String
'run'
kSplitKey → const String
'split'
kThemeKey → const String
'theme'