Restore Class Names in decay and mutators Folders for Backward Compatibility

[gitongah]

This pull request addresses the renaming of classes in the decay and mutators folders to their original names, ensuring backward compatibility with existing codebases that rely on these class names.

[knakamura13]

Added comments indicating changes that need to be made.

Also, before creating a pull request, try to make sure your branch is up to date with the main branch in my repo.
There are probably better ways to do this, but you can just follow these steps before you submit a pull request to sync my repo with yours:

1. git fetch upstream (or git fetch --all for simplicity)
2. git checkout main
3. git merge --ff-only upstream/main
4. git checkout <your PR branch>
5. git merge main (or git rebase main if you want)
6. git push

[knakamura13]

All imported classes should be renamed to the reverted names such as ArithDecay, ExpDecay, etc.

[knakamura13]

Still need to rename the imported GeometricDecay in src/mlrose_ky/algorithms/sa.py

[knakamura13]

I think the CI tests failed because the class names like GeometricDecay need to be removed from the __init__.py files and the new names need to be added to those files.

[github-actions]

Coverage report

Click to see where and how coverage changed

File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
src/mlrose_ky
__init__.py
src/mlrose_ky/algorithms
__init__.py
sa.py
src/mlrose_ky/algorithms/decay
__init__.py
arithmetic_decay.py					67
custom_decay.py					37, 43
exponential_decay.py					69
geometric_decay.py					67
src/mlrose_ky/algorithms/mutators
__init__.py
_mutator_base.py
discrete_mutator.py
gene_swap_mutator.py
single_gene_mutator.py
single_shift_mutator.py
src/mlrose_ky/generators
tsp_generator.py
src/mlrose_ky/neural
__init__.py
nn_core.py
src/mlrose_ky/neural/activation
identity.py
leaky_relu.py
sigmoid.py
src/mlrose_ky/opt_probs
discrete_opt.py
max_k_color_opt.py
src/mlrose_ky/runners
_nn_runner_base.py
_runner_base.py
tests
test_decay.py
Project Total

The report is truncated to 25 files out of 52. To see the full report, please visit the workflow summary page.

This report was generated by python-coverage-comment-action

[knakamura13]

Fixed the problems with miss-named class instances and all tests are passing now.
I'll merge this PR, but want to note that there are other classes that still need to be renamed in #7.

Thanks for the help on this!