[WIP] apply black to docs

[Remi-Gau]

• Relates to Possible "infra" improvements as recommend by scientific-python #4003

Changes proposed in this pull request:

• apply black to docs
• update pre-commit hooks

[github-actions]

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[codecov]

Codecov Report

Merging #4005 (ed970bb) into main (3f85e18) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #4005   +/-   ##
=======================================
  Coverage   91.77%   91.77%           
=======================================
  Files         134      134           
  Lines       15795    15795           
  Branches     3299     3299           
=======================================
  Hits        14496    14496           
  Misses        755      755           
  Partials      544      544           

Flag	Coverage Δ
macos-latest_3.10	91.69% <ø> (ø)
macos-latest_3.11	91.69% <ø> (ø)
macos-latest_3.8	91.65% <ø> (ø)
macos-latest_3.9	91.65% <ø> (ø)
ubuntu-latest_3.10	91.69% <ø> (ø)
ubuntu-latest_3.11	91.69% <ø> (ø)
ubuntu-latest_3.8	91.65% <ø> (ø)
ubuntu-latest_3.9	91.65% <ø> (ø)
windows-latest_3.10	91.63% <ø> (?)
windows-latest_3.11	91.63% <ø> (ø)
windows-latest_3.8	91.59% <ø> (ø)
windows-latest_3.9	91.60% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
nilearn/_utils/docs.py	91.86% <ø> (ø)
nilearn/datasets/atlas.py	93.14% <ø> (ø)
nilearn/plotting/displays/_projectors.py	98.24% <ø> (ø)
nilearn/plotting/displays/_slicers.py	90.88% <ø> (ø)

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[Remi-Gau]

Am not happy about having to use a noqa here but without it flake8 complains about line length and blacken docs will reformat any line break.

[Remi-Gau]

Will merge and open an issue to remember to find a fix for this minor detail

[bthirion]

LGTM, thx.