signal<T> function
Creates a new signal with the given initial value.
A signal is a reactive value that can be read and written to. When the value changes, any computed values or effects that depend on it will automatically update.
Example:
final count = signal(0);
effect(() {
print('Count is: ${count()}');
});
count(1); // Prints: Count is: 1
Implementation
WritableSignal<T> signal<T>(T value) => _WritableSignal(value);