Merge branch 'knepley/fix-plex-setup' into 'main'

Plex: Fix setup for RDycore

See merge request petsc/petsc!6877

Rename rules.doc and rules.utils because GitLab treats the former as a MS Word document.

Thanks-to: Jed Brown

Fix use of offdiagonal to off-diagonal

TS ex11: Use CEED for GPU support - Add CEED SW test - Add Euler test

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

Commit-type: housekeeping

Plex: Updates for FVM
- Add DMPlexInsertBoundaryValuesFVM()
- Add -dm_plex_print_fvm
- Fix copy of diagnostic flags

ExodusII; Fix check for reserved labels
- Disable check for many tests

Allowing automatic time step reduction in initial step.

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

Fix typos

Remove first and last empty lines

Merge remote-tracking branch 'origin/release'

Merge branch 'caidao22-main-patch-19448' into 'main'

Update ts.c

See merge request petsc/petsc!6778

Update ts.c

Fix ex9adj

DM+TS: Fix use of CHKERRQ

Need looser tolerance for TS test for Barry's macOS

Fix typos

Merge branch 'hongzh/improve-adjoint-arkimex' into 'main'

Improve adjoint ARKIMEX

See merge request petsc/petsc!6832

Improve adjoint ARKIMEX

Merge branch 'hongzh/fix-ark-scoeff' into 'main'

Reconcile the conflict on ark->scoeff

See merge request petsc/petsc!6831

Reconcile the conflict on ark->scoeff

Convert all header guards to pragma once

Fix some malformed if !defined() header guards

Merge branch 'jacobf/2023-08-09/linter-detect-static-function-candidates' into 'main'

Linter detect possible static functions

See merge request petsc/petsc!6796