Avoid using `forEach` with a function literalDRT-W1055

AVOID using forEach with a function literal.

The for loop enables a developer to be clear and explicit as to their intent. A return in the body of the for loop returns from the body of the function, where as a return in the body of the forEach closure only returns a value for that iteration of the forEach. The body of a for loop can contain awaits, while the closure body of a forEach cannot.

BAD:

people.forEach((person) {
  ...
});

GOOD:

for (var person in people) {
  ...
}