feat: if a function is analytic on a set, its derivative also is, eve…

…n if the space is not complete (#17221)

We already have a version of this theorem, but assuming completeness while this is not necessary: if the function is differentiable, then the power series for its derivative converges, to the given differential (since this is the case in the completion, and the embedding in the completion is an embedding).

This result requires expanding the API around derivatives of analytic functions. As a byproduct, we also write down the derivative of linear maps into multilinear maps (which will be needed for the Faa di Bruno formula).