Deconstruct variable declaration

Example

// csharp_style_deconstructed_variable_declaration = true
var (name, age) = GetPersonTuple();
Console.WriteLine($"{name} {age}");

(int x, int y) = GetPointTuple();
Console.WriteLine($"{x} {y}");

// csharp_style_deconstructed_variable_declaration = false
var person = GetPersonTuple();
Console.WriteLine($"{person.name} {person.age}");

(int x, int y) point = GetPointTuple();
Console.WriteLine($"{point.x} {point.y}");