Improve the readability and maintainability of test_capi using the AC

[corona10]

Currently, most of test_capi modules do not use the Argument Clinic tool.
As a result, we manually implement docstrings containing explanations for the test codes and handle parameter parsing manually: PyArg_ParseTuple .
To maintain code consistency in test_capi, I suggest using the Argument Clinic tool.

While some might criticize this as code churn, I believe it is necessary for maintaining consistent test code writing practices. I will attach a sample PR to illustrate how it can help improve the understanding of the test code. I hope this will help clarify the rationale behind it.

cc @erlend-aasland @sobolevn

Linked PRs

• gh-104469 Convert _testcapi/float.c to use AC #104470
• gh-104469 Convert _testcapi/exceptions to use AC #104502
• gh-104469: Convert _testcapi/watchers.c to use AC #104503
• gh-104469: Update README.txt for _testcapi #104529
• gh-104469: Convert _testcapi/long to use AC #104720
• gh-104469 Convert_testcapi/vectorcall.c to use AC #106557
• gh-104469 : Convert _testcapi/vectorcall_limited.c to use AC #107857
• gh-104469 : Convert _testcapi/dict.c to use AC #107859
• gh-104469 : Convert _testcapi/mem.c to use AC #107860
• Revert "gh-104469 : Convert _testcapi/vectorcall_limited.c to use AC … #107951
• gh-104469 Fix limited C API issue for WASI #107953
• gh-104469: Disallow using Py_LIMITED_API with Py_BUILD_CORE #109690
• gh-104469: Convert _testcapi/vectorcall_limited.c to use AC #109691

[sunmy2019]

LGTM

[corona10]

I am working on test_exceptions.

[sobolevn]

I am working on _testcapi/watchers.c 👍

[erlend-aasland]

Let's establish some guidelines:

• For the sake of readability (which is one of the goals here), please add a newline between the argument spec and the docstring
• If purpose is obvious given a function name, omit the docstring
• If a description is needed, make sure the added docstring clearly and succinctly describes purpose of the function
• DRY, use the clone feature of Argument Clinic
• Try to avoid adding new interned strings; reuse existing parameter names if possible and use the as feature to override the C name

cc. @sobolevn @corona10