Add encoding argument to from_asc()

[saeub]

Description

RaCCooNS (#961) uses non-ASCII .asc files. This PR should allow specifying the encoding using custom_read_kwargs as with .csv files.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change is or requires a documentation update

How Has This Been Tested?

• test_parse_eyelink_encoding

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (0913c23) to head (a746f01).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #989   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files           78        78           
  Lines         3557      3557           
  Branches       622       622           
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  Hits          3557      3557           

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[saeub]

@SiQube pls review 🥺

[SiQube]