Add more documentation

[cbaker6]

This adds missing documentation to methods and properties that have already been public and available.

• Minor internal updates to ParseAnonymous and ParseAuthentication. The argument for authData is no longer optional, but this shouldn't be a breaking change as 1) you can't login by passing authData = nil, so they are already passing a non-nil dictionary, 2) most devs are using the other methods to login instead of passing authData directly. This change allows us to simplify some of the code internally. Also fixed a ParseAnonymous testcase that can randomly cause a threading error.
• Improved codecov for ParseAnonymous, ParseApple, and ParseLDAP
• Fixed some threading issues in the test cases, particularly with ParseACLTests where the url mocker wasn't being removed when tests complete. This could interfere with the tests that run directly after.

[codecov]

Codecov Report

Merging #96 (0aeae38) into main (a99bf31) will increase coverage by 0.62%.
The diff coverage is 100.00%.

❗ Current head 0aeae38 differs from pull request most recent head 1a00733. Consider uploading reports for the commit 1a00733 to get more accurate results

@@            Coverage Diff             @@
##             main      #96      +/-   ##
==========================================
+ Coverage   79.10%   79.72%   +0.62%     
==========================================
  Files          63       63              
  Lines        5179     5170       -9     
==========================================
+ Hits         4097     4122      +25     
+ Misses       1082     1048      -34     

Impacted Files	Coverage Δ
...Authentication/Protocols/ParseAuthentication.swift	70.09% <ø> (ø)
Sources/ParseSwift/Objects/ParseObject.swift	76.13% <ø> (-1.09%)	⬇️
...rseSwift/Authentication/3rd Party/ParseApple.swift	89.02% <100.00%> (+23.71%)	⬆️
...arseSwift/Authentication/3rd Party/ParseLDAP.swift	100.00% <100.00%> (+24.35%)	⬆️
...Swift/Authentication/Internal/ParseAnonymous.swift	100.00% <100.00%> (+20.00%)	⬆️
Sources/ParseSwift/Objects/ParseUser.swift	79.16% <100.00%> (ø)
Sources/ParseSwift/Operations/ParseOperation.swift	75.72% <100.00%> (+0.28%)	⬆️
Sources/ParseSwift/Types/Query.swift	90.78% <100.00%> (+0.15%)	⬆️
...cation/Protocols/ParseAuthentication+combine.swift	40.00% <0.00%> (-48.00%)	⬇️
Sources/ParseSwift/Coding/ParseCoding.swift	89.13% <0.00%> (-2.18%)	⬇️
... and 5 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a99bf31...1a00733. Read the comment docs.