More operators inside `is(...)` expressions

[Per Nordlöw]

On Sunday, 23 August 2020 at 22:11:41 UTC, Steven Schveighoffer 
wrote:
> static if (is(int != T))
> {
>    // use T
> }

Furthermore, what's wrong with allowing

static if (int is T)
{
    // use T
}

static if (int !is T)
{
    // use T
}

?

Less syntax for developer to remember.