Following the update of index.rst, a corresponding update of index.ipynb is necessary.

The `pydot_ng` recommendation should definitely be dropped since that project is officially archived in favor of pydot: https://github.com/pydot/pydot-ng

* Use better ASCII symbols
* Show continuation hint for already seen nodes
* Don't repeat entries for multiple output inner graphs

* Add failed assertion message in CI

* Pin numpy upper bound in numba install

numba-scipy downgrades the installed scipy to 1.7.3 in Python 3.8, but not numpy, even though scipy 1.7 requires numpy<1.23. When installing PyTensor next, pip installs a lower version of numpy via the PyPI.

* Run numba and jax tests in separate jobs

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Co-authored-by: Ben Mares <services-git-throwaway1@tensorial.com>

Supposed to be removed in 6d431aa6

Moving caused a circular dependency with tensor.blas. It seems most
linalg rewrites are in the stablize set, so should run before the blas
specializers anyway, so these checks were removed.

This also deleted the unused `spectral_radius_bound` and dummy
`Minimal(Op)`.

Having Ops and rewrites in the same files was causing circular imports.

This reverts commit 277559b4.

Fixes #309

This was problematic when OpenMP was used in the Elemwise outer loop

We add one extra output flag stating whether iteration converged or not. This however breaks Hyp2F1 grad in python mode because it goes beyond the Elemwise limit on number of operands. To fix it we split the grad when on python mode