Moving Sphinx dependencies back out of dev.

[bmaher]

Attempt to fix failing docs build.

Part of #5.

Description

It seems like Read The Docs' build fails if they there. Copied the full configuration from Transformer.

Types of Changes

What types of changes does your code introduce? Keep the ones that apply:

• Configuration change

Review

Reviewers' checklist:

• If this PR implements new flows or changes existing ones, are there good tests for these flows? If this PR rather removes flows, are the obsolete tests removed as well?
• Is the documentation still up-to-date and exhaustive? This covers both technical (in source files) and functional (under docs/) documentation.
• Is the changelog updated?
• Does the new version number correspond to the actual changes from this PR? In doubt, refer to https://semver.org.

[zincr[bot]]

🤖 zincr found 0 problems , 1 warning

ℹ️ Dependency Licensing
✅ Large Commits
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✅ Specification

Details on how to resolve are provided below

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Dependency Licensing

All dependencies specified in package manager files must be reviewed, banned dependency licenses will block the merge, all new dependencies introduced in this pull request will give a warning, but not block the merge

Please ensure that only dependencies with licenses compatible with the license of this project is included in the pull request.

• ℹ️ Detected sphinx as a dependency in pyproject.toml, licensed under: BSD-2-Clause please review it and confirm you wish to introduce this to the codebase
• ℹ️ Detected sphinx-autodoc-typehints as a dependency in pyproject.toml, licensed under: MIT please review it and confirm you wish to introduce this to the codebase
• ℹ️ Detected sphinx-issues as a dependency in pyproject.toml, licensed under: MIT please review it and confirm you wish to introduce this to the codebase