chore: fix editor autocompletion

[alexander-held]

This fixes code autocompletion for vscode (IntelliSense) by importing the cabinetry components differently in the top-level __init__.py. Previously they were accessible only via cabinetry.cabinetry. histo was previously missing here and is also added, and an appropriate top-level __all__ is also defined.

* fixed editor autocompletion by appropriately importing cabinetry components
* added top-level __all__
* updated pre-commit

[codecov[bot]]

Codecov Report

Base: 100.00% // Head: 99.95% // Decreases project coverage by -0.04% :warning:

Coverage data is based on head (e3935ac) compared to base (db0e728). Patch coverage: 92.85% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #386 +/- ## =========================================== - Coverage 100.00% 99.95% -0.05% =========================================== Files 23 23 Lines 2041 2046 +5 Branches 324 324 =========================================== + Hits 2041 2045 +4 - Misses 0 1 +1 ``` | [Impacted Files](https://codecov.io/gh/scikit-hep/cabinetry/pull/386?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=scikit-hep) | Coverage Δ | | |---|---|---| | [src/cabinetry/\_\_init\_\_.py](https://codecov.io/gh/scikit-hep/cabinetry/pull/386?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=scikit-hep#diff-c3JjL2NhYmluZXRyeS9fX2luaXRfXy5weQ==) | `95.00% <92.85%> (-5.00%)` | :arrow_down: | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=scikit-hep). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=scikit-hep)

:umbrella: View full report at Codecov.
:loudspeaker: Do you have feedback about the report comment? Let us know in this issue.