Update Pathlib usage and docstrings

[willGraham01]

Description

What is this PR

• [ ] Bug fix
• [ ] Addition of a new feature
• [x] Other

Why is this PR needed?

Standardises our imports of pathlib Paths and avoids importing the whole module when we only need the Path class.

What does this PR do?

• Standardises our import of Path to from pathlib import Path across the package.
• Updates / adds docstrings to a few functions that reply on Path inputs.

References

No issues, but picked up on in a comment on https://github.com/brainglobe/brainglobe-utils/pull/65#issuecomment-2046963476

How has this PR been tested?

Tests pass locally. No package functionality should be changed, either.

Is this a breaking change?

No.

Does this PR require an update to the documentation?

N/A

Checklist:

• [x] The code has been tested locally
• [x] Tests have been added to cover all new functionality (unit & integration)
• [x] The documentation has been updated to reflect any changes
• [x] The code has been formatted with pre-commit

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 90.54%. Comparing base (3b632c2) to head (27cdba4).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #68 +/- ## ========================================== - Coverage 90.56% 90.54% -0.02% ========================================== Files 35 35 Lines 1356 1364 +8 ========================================== + Hits 1228 1235 +7 - Misses 128 129 +1 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.

[willGraham01]

CodeCov doesn't like my TYPE_CHECKING imports in files where we don't actually need to instantiate a Path object.

Happy to change those to regular imports on reviewer's request to avoid the red-cross-of-doom :sweat_smile:

[willGraham01]

For the TYPE_CHECKING imports I wonder if there's a way to exclude these lines from codecov https://github.com/nedbat/coveragepy/issues/831#issuecomment-517778185?

Went for the straight-up import solution :sweat_smile: The solution given in the linked issue seems to imply that the .coveragerc file should be on a per-repo basis, and I don't want to escalate this PR to setting a precedent for the whole project. The #pragma: no cov solution is also ugly to include in each of the blocks (and could very easily get misplaced after a few edits if imports are moved around / changed).

[willGraham01]

where quotes are no longer needed around the types

VSCode linter why have you forsaken me :sob: