DOC incorporate type annotations in docs

[Badagala Bharath Kumar (Bharath-kumar-7)]

Summary

This PR addresses #1428 by incorporating the existing type annotations into the generated documentation and restoring signatures for singledispatch methods.

Changes

• Set autodoc_typehints to "signature" so type annotations are included in API signatures.
• Remove the avoid_duplicate_in_dispatch workaround that was introduced in Temporarily disable typehints and singledispatch in function signatures #606.
• Keep the documentation configuration focused on the existing type annotations in the .pyi stubs.

Testing

• python -m py_compile docs/source/conf.py
• git diff --check

Closes #1428

[CLAassistant]

All committers have signed the CLA.

[Coveralls (coveralls)]

Coverage Report for CI Build 37588752843

Coverage remained the same at 94.692%

Details

• Coverage remained the same as the base build.
• Patch coverage: No coverable lines changed in this PR.
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	20308
Covered Lines:	19230
Line Coverage:	94.69%
Coverage Strength:	1136621.19 hits per line

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💛 - Coveralls