Log warning when sf or ch_names are ignored

[remrama]

This minor PR adds clarification surrounding a question in #156 about the ch_names parameter. I'm just implementing direct suggestions from there to provide clarity for the user:

1. Add clarification in the docstrings
2. Add a user warning when arguments are provided by user but ignored by YASA

Raising an AssertionError instead of a warning might make more sense, as assertion checks are used in the opposite case a few lines later (i.e., when data is specified and sf is not). But I didn't want to break anyone's existing code in case they passed sf through for logistical reasons or something. Happy to change if anyone prefers it as a raised error.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.44%. Comparing base (c18f1a6) to head (b628c3c).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #207      +/-   ##
==========================================
+ Coverage   77.40%   77.44%   +0.03%     
==========================================
  Files          14       14              
  Lines        2678     2682       +4     
  Branches      324      326       +2     
==========================================
+ Hits         2073     2077       +4     
  Misses        568      568              
  Partials       37       37              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.