Proposed number style

This has come up a few times.

I generally think any unnecessary type in a number literal is silly, because it just makes it more fragile and more work to change later (if the type of the variable, constant, etc. changes). I also prefer reading this:

```objc
CGRect rect = { .x = 5, .y = 10, .width = 50, .height = 50 };
```

to this:

```objc
CGRect rect = { .x = 5.0, .y = 10.0, .width = 50.0, .height = 50.0 };
```

And I think we can all agree that @alanjrogers' `5.` is horrific. :wink: