Review exp_overapproximation name

[mforets]

In the context of IA, all functions may overapproximate, so I suggest to rename what is now exp_overapproximate to just exp.

[schillic]

I think this was meant in contrast to exp_underapproximation. I do not remember if that is really an underapproximation of the true result or (my preference) it is just an underapproximation of exp_overapproximate. Note that the docstring is not helpful because I think it just has a typo there.

IntervalMatrices.jl/src/exponential.jl

Lines 319 to 321 in a892aed

	exp_underapproximation(M::IntervalMatrix{T, Interval{T}}, t, p) where {T}
	Overapproximation of the exponential of an interval matrix.

[lucaferranti]

what is an underapproximation of an overapproximation? Is it computed by some probablistic algorithm which may leave out a portion x of the true solution set?

[schillic]

No, I meant just a subset of the overapproximation.
But I checked again and I think I have to correct myself: here it is really an underapproximation of the exact result.