Make self-diffeomorphisms default

[tobiasdiez]

Currently, if you construct a diffeomorphism from a manifold to itself, you have to specify the manifold as the codmain. With the changes in this ticket, this is no longer necessary and we assume that the user want's to specify a self-diffeomorphism if no codomain is given.

CC: @tscrim @nthiery @mjungmath @egourgoulhon @mkoeppe

Component: manifolds

Author: Tobias Diez

Branch/Commit: 54d4cd3

Reviewer: Travis Scrimshaw

Issue created by migration from https://trac.sagemath.org/ticket/31323

[tscrim]

comment:2

Seems very reasonable and is in line with Hom. LGTM.

[tscrim]

Reviewer: Travis Scrimshaw

[egourgoulhon]

comment:3

Thanks for this improvement!

Side comment: when you open a ticket like this, could you please add it to the metaticket #30525 ? This helps keeping track on what's going on, especially to prepare the release tours and the changelogs. I've just done it for this ticket, as well as for #31322.
Moreover the Cc field of Track is not 100% reliable (recently I've not been notified about some ticket while my username was added in Cc; such an issue has been already reported by others in the past).

[tobiasdiez]

comment:4

Thanks!

Next time I'll also add them to the metaticket.

[vbraun]

Changed branch from public/manifolds/diffeo_self_default to 54d4cd3