Fix generator issues

[michalina-majewska]

1. Support multiple parameters with the same type e.g.

String helloEveryone(String person1, String person2, String person3);

2. Replace hardcoded class name in the template.

3. Support multiline method signatures e.g.

String reallyLongNameThatWillCauseDartFormatterToSplitLines(
    String parameter1,
    String parameter2,
);

2 and 3 can be solved by using the default L10n class name and turning off the dart formatter but 1 needed a real fix.

[wzslr321]

Bump 🏄