Exclude atom tests data from pre-commit processing and fix typo

Test Plan

Due to the recent bump of codespell, new spelling errors were reported.

pre-commit run --all-files
trim trailing whitespace.................................................Passed
check json...............................................................Passed
check yaml...............................................................Passed
flake8...................................................................Passed
Check source code spelling...............................................Failed
- hook id: codespell
- exit code: 65

swh/deposit/tests/data/atom/codemeta-sample.xml:36: Projet ==> Project
swh/deposit/tests/data/atom/codemeta-sample.xml:37: projet ==> project
swh/deposit/tests/data/atom/codemeta-sample.xml:42: Projet ==> Project
swh/deposit/tests/data/atom/codemeta-sample.xml:43: Projet ==> Project
docs/api/metadata.rst:107: Projet ==> Project

mypy.....................................................................Passed
isort....................................................................Passed
black....................................................................Passed
make: *** [../Makefile.python:28: check] Error 1

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Migrated from D8746 (view on Phabricator)