fix(dart_frog_cli): `dart_frog new` doesn't allow the creation of wildcard routes.

[renancaraujo]

Description

dart_frog new doesn't allow the creation of wildcard routes.

Steps To Reproduce

dart_frog new route "/[...nice]"

Throws an error "Route path segments must be valid Dart identifiers"

Expected Behavior

This should create a wildcard route.

[ZhongGuanbin]

i have the same question