isDotAll property Null safety
Whether "." in this regular expression matches line terminators.
When false, the "." character matches a single character, unless that character is a line terminator. When true, then the "." character will match any single character including line terminators.
This feature is distinct from
isMultiline, as they affect the behavior
of different pattern characters, and so they can be used together or
@Since("2.4") bool get isDotAll;