Remove references to mlir-hlo in docs

[joeycarter]

Catalyst no longer uses the mlir-hlo package, but we still reference it in a number of places in our docs, e.g.

catalyst/doc/dev/architecture.rst

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`mlir-hlo <https://github.com/tensorflow/mlir-hlo>`_ project.

catalyst/doc/dev/installation.rst

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<https://mlir.llvm.org/>`_ and `MLIR-HLO

catalyst/doc/dev/installation.rst

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	To make required tools in ``llvm-project/build``, ``mlir-hlo/mhlo-build``, and
	``mlir/build`` discoverable to the compiler:

catalyst/doc/dev/installation.rst

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	export PATH="$PWD/mlir/llvm-project/build/bin:$PWD/mlir/mlir-hlo/mhlo-build/bin:$PWD/mlir/build/bin:$PATH"

catalyst/doc/dev/debugging.rst

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	- **HLO (XLA) + Quantum Dialect**: Lowering to `HLO <https://github.com/tensorflow/mlir-hlo>`_ is the first stage inside MLIR after leaving JAXPR.
	- **Builtin + Quantum Dialects**: HLO is then converted to a variety of classical dialects in MLIR.

The docs should be updated to reflect the recent migration from mlir-hlo to stablehlo (see #1921 for details).