Reimplement Box.Inflate with System.Drawing matching functionality

[NogginBops]

Description

In #1511 and #1615 Box.Inflate got marked as Obsolete pending a change to the functionality of the function to match System.Drawing.Rectangle.Inflate.

We should add a remark in the documentation of Box.Inflate that it used to do something else so that someone who is upgrading from 4.7.7 -> 4.8.2 has any chance to find the issue when debugging.

[NogginBops]

Going to target this for 4.8.2 instead.

[MV10]

@NogginBops so basically re-implement this from #1455 ?

e61afa3

public void Inflate(Vector2 size)
{
    size = Vector2.ComponentMax(size, -HalfSize);
    _min -= size;
    _max += size;
}

public Box2 Inflated(Vector2 size)
{
    // create a local copy of this box
    Box2 box = this;
    box.Inflate(size);
    return box;
}

Here's the .NET 7 implementation (src):

public void Inflate(int width, int height)
{
    unchecked
    {
        X -= width;
        Y -= height;

        Width += 2 * width;
        Height += 2 * height;
    }
}

[MV10]

I have this ready to PR, but I thought I'd go the extra mile and implement a real Inflate test, which the older PR did not.

I'm no F# expert (I'm not even an F# amateur), nor am I a fan of unit tests, but I think this right. However, it fails due to what looks to me like a rounding error between C# and F#... How the heck do you deal with that? (And this is why I hate unit tests, anything non-trivial is essentially "rewriting the same code a slightly different way" and I inevitably spend more time debugging tests than real code.)

module Inflate =
    [<Property>]
    let ``Box2.Inflate produces the expected min and max changes`` (b1 : Box2, v1 : Vector2) =
        let size = Vector2.ComponentMax(v1, -b1.HalfSize);
        let b = Box2(b1.Min - size, b1.Max + size)
        Assert.Equal(b, b1.Inflated(v1))

Note "expected" from F# is -0.0739928 but actual from C# is -0.07399279:

 OpenTK.Tests.Box2+Inflate.Box2.Inflate produces the expected min and max changes
   Source: Box2Tests.fs line 161
   Duration: 105 ms

  Message: 
FsCheck.Xunit.PropertyFailedException : 
Falsifiable, after 1 test (0 shrinks) (StdGen (613089187, 297245411)):
Original:
((-0.3379175, -1.2313157) - (0.18993191, 0.104034156), (-0.9891462, 0.027614703))

---- Assert.Equal() Failure
Expected: (-0.0739928, -1.2589304) - (-0.07399279, 0.13164885)
Actual:   (-0.07399279, -1.2589304) - (-0.0739928, 0.13164885)

Maybe this is why the earlier PR skipped it?