Cleanup and fix coarsening methods and harden ASM blocks from coarsening

Merge remote-tracking branch 'origin/release'

Merge branch 'MarDiehl-release-patch-49563' into 'release'

fixing typesetting issue in DMPLEX introduction

See merge request petsc/petsc!6978

Merge branch 'release'

not actual code, rather a comment for clarification

Increase patchlevel to 3.20.1

Remove unneeded on in Collective statements and fix Collective over

Commit-type: documentation

some parts are missing (on Firefox and Chrome), probably due to overlong line (https://nextcloud.cs.kuleuven.be/s/Y5zAGHaqK3XAZe6).

Add VecGhostGetGhostIS to get the ghost indices of a ghosted vector

And do not create ISLocalToGlobalMapping in VecGhost by default

Co-authored-by: Alex Lindsay <alexander.lindsay@inl.gov>

Added hook to set number of iteration in HEM coarsener

Merge branch 'jczhang/2023-10-16/feature-persistent-mpi-nbr' into 'main'

SF: Add MPI-4.0 persistent MPI neighborhood collectives support

See merge request petsc/petsc!6943

Merge branch 'knepley/feature-plex-high-order-view' into 'main'

Plex: Enable high order viewing

See merge request petsc/petsc!6959

PetscSF: add MPI-4.0 persistent neighborhood collectives support

Plex: Enable high order viewing - Refinement recreates affine coordinates - Default for draw viewer - Replace DMProjectCoordinates() with DMSetCoordinateDisc() - Add argument to DMPlexCreateCoordinat

Plex: Enable high order viewing - Refinement recreates affine coordinates - Default for draw viewer - Replace DMProjectCoordinates() with DMSetCoordinateDisc() - Add argument to DMPlexCreateCoordinateSpace()

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Merge remote-tracking branch 'origin/release'

Fix Sphinx warning "The default value for `navigation_with_keys` will change to `False`" that stops docs build in petsc4py

Merge branch 'barry/2023-10-18/rm-dirs-from-makefiles' into 'main'

Remove use of and the DIRS variables from the makefiles

See merge request petsc/petsc!6945

Remove tabs from petsc.bib file

Remove DIRS variable and unneeded tabs from all makefiles since no longer needed

Commit-type: housekeeping

Merge remote-tracking branch 'origin/release'

Fix stale URL/wrong bib entry displayed on website (fix #1483)

The old key name conflicted with literalinclude for petsc-web-page.

Reported-by: Tomáš Luber

Minor documentation fixes

Merge remote-tracking branch 'origin/release'

Allowing automatic time step reduction in initial step.

Adding option for custom predictor in 2nd-order generalized-alpha time integrator.