…rived methods

…SpanFormattable`

Introduced a test to skip `ToString` methods that implement an interface in the snapshot tests. Also modified the code generation logic to change ToString method generation to use parameters instead of items and added a detailed method documentation.

Cleaned up the GenerateCodeForToString.cs file by eliminating several blocks of commented-out code. This improves readability and maintains a cleaner codebase.

This commit simplifies the code by removing commented-out `createChangedSolution` lines in both `AddMethodCodeFixProvider` and `AddStaticToExistingMethodCodeFixProvider` classes. This helps to clean up the code and ensure that only the necessary logic is present.