docs: Update docs of MetaFieldRanker, TransformersSimilarityRanker

[julian-risch]

Related Issues

• fixes Docstrings - haystack.components.rankers #7112

Proposed Changes:

• Update docstrings of MetaFieldRanker, TransformersSimilarityRanker
• Remove to_dict/from_dict that just uses the default implementation and the corresponding tests. There is no reason to test the default implementation of component_to_dict(obj).

How did you test it?

Notes for the reviewer

LostInTheMiddleRanker was done in a separate PR: #7294

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:.
• I documented my code
• I ran pre-commit hooks and fixed any issue

[coveralls]

Pull Request Test Coverage Report for Build 8153447014

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 17 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.003%) to 90.051%

---

Files with Coverage Reduction	New Missed Lines	%
components/rankers/transformers_similarity.py	8	90.91%
components/readers/extractive.py	9	95.69%

Totals
Change from base Build 8143319828:	-0.003%
Covered Lines:	5286
Relevant Lines:	5870

---

💛 - Coveralls

[anakin87]

Approved with some minor comments. (Feel free to consider or discard them.)

I appreciated your efforts to better explain what is going on in the Components.

[anakin87]

Generally, I had no luck with rendering bulleted lists inside params. I always got a flat list.
Please check locally if the generated markdown is ok.