Added math module back into pre-commit. Renamed classes following capitalization conventions.

[SamuelBorden]

@gipert I've added the math module back into the pre-commit. I changed some variable names to all lowercase, and then changed all math distribution class names to uppercase. I fixed the imports related to this in math and pargen and fixed some docstrings that weren't compiling in pargen. Tests in math and pargen are still passing for me locally.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 67.03297% with 210 lines in your changes are missing coverage. Please review.

Project coverage is 50.05%. Comparing base (9b2e556) to head (ebfbe4c).

Files	Patch %	Lines
src/pygama/math/histogram.py	59.13%	47 Missing :warning:
src/pygama/math/hpge_peak_fitting.py	66.23%	26 Missing :warning:
src/pygama/math/functions/exgauss.py	52.63%	18 Missing :warning:
src/pygama/math/functions/sum_dists.py	77.21%	18 Missing :warning:
src/pygama/math/functions/gauss.py	39.28%	17 Missing :warning:
src/pygama/math/functions/crystal_ball.py	57.14%	15 Missing :warning:
src/pygama/math/functions/step.py	61.76%	13 Missing :warning:
src/pygama/math/functions/exponential.py	66.66%	8 Missing :warning:
src/pygama/math/functions/hpge_peak.py	55.55%	8 Missing :warning:
src/pygama/math/functions/poisson.py	53.33%	7 Missing :warning:
... and 7 more

Additional details and impacted files

```diff @@ Coverage Diff @@ ## refactor #576 +/- ## ============================================ - Coverage 50.36% 50.05% -0.31% ============================================ Files 63 63 Lines 7581 7581 ============================================ - Hits 3818 3795 -23 - Misses 3763 3786 +23 ```

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[gipert]

lovely, thanks a lot sam!