docs: Give example of a non-generic signature

[epage]

Trying to balance documentation-overload with helping new users who might be uncomfortable with the generics. Was a bit hesitant if this met that balance but my mastadon poll seemed to be in favor.

• Didn't do this to parsers like opt or repeat where there is nothing concrete to work with
• Skipped binary because that is a lot of repetition that I didn't want to take on atm

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 41.85%. Comparing base (aaed6ae) to head (dc41fcd).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #486      +/-   ##
==========================================
+ Coverage   41.82%   41.85%   +0.03%     
==========================================
  Files          18       18              
  Lines        3046     3046              
==========================================
+ Hits         1274     1275       +1     
+ Misses       1772     1771       -1     

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[coveralls]

Pull Request Test Coverage Report for Build 8101333327

Details

• 1 of 1 (100.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.03%) to 41.858%

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Totals
Change from base Build 8083360033:	0.03%
Covered Lines:	1275
Relevant Lines:	3046

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💛 - Coveralls