feat: support rest-style docstrings when loading tools from function

[LastRemote]

Related Issues

#9023

Proposed Changes:

Supports ReST-style docstrings when loading a tool from function. The docstring will be automatically parsed for function-level descriptions and parameter descriptions. It's a small feature due to the fact that I was too lazy to write parameter annotations in class and instance methods.

How did you test it?

Added a new unit test for it.

Notes for the reviewer

N/A

Checklist

• I have read the contributors guidelines and the code of conduct
• I have updated the related issue with new insights and changes
• I added unit tests and updated the docstrings
• I've used one of the conventional commit types for my PR title: fix:, feat:, build:, chore:, ci:, docs:, style:, refactor:, perf:, test: and added ! in case the PR includes breaking changes.
• I documented my code
• I ran pre-commit hooks and fixed any issue

[LastRemote]

P.S. Parameter and return type definitions in ReST docstrings are currently ignored to avoid things being too complicated.

[coveralls]

Pull Request Test Coverage Report for Build 13759572106

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.03%) to 89.965%

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Totals
Change from base Build 13718432299:	0.03%
Covered Lines:	9718
Relevant Lines:	10802

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💛 - Coveralls

[LastRemote]

@anakin87 Sure thing, here is the GH issue: https://github.com/deepset-ai/haystack/issues/9023