Change PETSc sys typedef function names to use the new _Fn format

Commit-type: housekeeping, maintainance

add typedef for functions passed to SNESSetFunction() etc to match approach in TS

I never liked Jed's use of typedef for function prototypes for a couple of reasons

1) you don't see immediately tha

add typedef for functions passed to SNESSetFunction() etc to match approach in TS

I never liked Jed's use of typedef for function prototypes for a couple of reasons

1) you don't see immediately that the argument to the function is a function pointer instead of standard variable when looking at source
2) you don't see at the exact location in the code the prototype of the function being passed in

but there is something to say for using these typedefs so

I've prototyped the change for SNES but slightly differently than what Jed did for TS

1) I append the typedef with _Ftn to mark that it is a function (helping to relieve the problem 1 above)
2) I made the typedef to be for a function, not a function pointer so it can also be used directly for things like

PETSC_EXTERN SNESJacobian_Ftn SNESComputeJacobianDefault;

I think the TS usage could be switched to this style without user code breakage, and deprecate the current TS typedef

Thoughts?

Just do SNES the same way as TS and live with less clarity?

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Merge branch 'stefanozampini/dmplexforest' into 'main'

Updates to DMPLEX and DMFOREST

See merge request petsc/petsc!7217

DMPLEXFEM: fix auxiliary vector cases

Use PetscTryTypeMethod when possible

Fix manual pages for dmadapt and dminterpolationinfo that have been moved

mv dminterpolate and dmadapt routines to subdirectory so they can have proper MANSEC value of DM

Merge branch 'barry/2023-12-22/rm-libbase' into 'main'

LIBBASE is no longer used in make so remove it

See merge request petsc/petsc!7139

Merge remote-tracking branch 'origin/release'

Clarify docs for MatCreateSNESMF().

Reported-by: Yi Hu <y.hu@mpie.de>

LIBBASE is no longer used in make so remove it

Merge branch 'stefanozampini/minsurf-local' into 'main'

Improve support for nonlinear domain decomposition solvers

See merge request petsc/petsc!7084

DMPLEX: add support for DMCreateDomainDecomposition routines

DMPlexDistributeOverlap: add support for subdomain mesh

DMPLEXSNES: support objective functions

Merge remote-tracking branch 'origin/release'

Fix -Wzero-as-null-pointer-constant errors