Request: Expanded documentation for several functions

[mnkwarshie]

Request: Expanded documentation for several functions

Summary
Several functions in rcmdcheck have minimal documentation, which makes it difficult to understand expected inputs, outputs, and behaviour without reading the source code directly.

Affected functions

• compare_checks() — the cmp field in the return value is undocumented (the Value section simply says cmp: with no description)
• cran_check_results() — no details on the structure of the returned list of rcmdcheck objects
• parse_check() — no description of the fields in the returned rcmdcheck object
• parse_check_url() — only documents the url and quiet arguments and states the return is an rcmdcheck object, but gives no detail on the expected URL format beyond "no HTML markup", and no description of the fields in the returned object
• rcmdcheck() — the Value section describes only errors, warnings, and notes, but the returned object contains many additional fields (e.g. stdout, platform, session_info, test_output)

Suggested improvements

• Document all fields of the rcmdcheck_comparison object returned by compare_checks(), particularly cmp
• Document all fields of the rcmdcheck object consistently across functions that return one
• Add a clear example of a valid URL format for parse_check_url(), e.g. the .txt endpoint from the CRAN check results page
• Add examples where they are currently missing

Context

I ran into these gaps while writing tests against the package's output. Having more complete documentation would make it much easier to write reliable downstream code without needing to inspect objects manually.

Thanks for maintaining this package!