prefer_double_quotes

Unnecessary use of single quotes.

The analyzer produces this diagnostic when a string literal uses single quotes (') when it could use double quotes (") without needing extra escapes and without hurting readability.

The following code produces this diagnostic because the string literal uses single quotes but doesn't need to:

void f(String name) {
  print('Hello $name');
}

Use double quotes in place of single quotes:

void f(String name) {
  print("Hello $name");
}