Second CT-Parameter of isRange Predicates

[Nordlöw via Digitalmars-d]

Is there a reason why

     isOutputRange(R,E)

takes a second argument `E` but not other range predicates

     isInputRange(R)
     isForwardRange(R)
     ...

?

If so, I still think it would very be nice to have a second 
argument `E` for all the other `isXRange` traits to simplify, for 
instance,

     if (isInputRange!R && is(int == ElementType!R))

to simpler

     if (isInputRange!(R, int))

or even

     if (isInputRange!R && is(isSomeChar!(ElementType!R)))

to simpler

     if (isInputRange!(R, isSomeChar))

?

What do think?

I'm planning to add a PR for this and simplify Phobos in all 
places where this pattern is used.