require-variable-type: Turn off for function expressions

[lararosekelley]

Would be helpful to be able to have a setting such as excludeFunctionExpressions or something so that I can write code like this:

const myFunc = function myFunc: boolean {
    return true;
};

It's just so redundant to have to write something like this when using named function expressions:

const myFunc: Function = function myFunc(): boolean {
    return true;
};