Move File.readable?, .writable?, .executable? to File::Info

[straight-shoota]

These methods provide lower-level insights into the file system. Their use cases are rare and exposure in the top-level File namespace is confusing due to the similarly-named methods File.read and File.write.

Resolves part of #14245

[ysbaddaden]

I'm wondering about the policy around deprecated methods and their documentation: shall we keep the doc comment, only have the Deprecated annotation, add a See Type#method link (which maybe the Deprecated annotation could handle)?

[straight-shoota]

It's probably best to keep the current documentation. The method still works like that and deprecation is just a friendly indicator for future changes.

The deprecation message typically refers to the replacement (which is implicitly linked). So there's no need for an explicit See XY.

[crysbot]

This pull request has been mentioned on Crystal Forum. There might be relevant details there:

https://forum.crystal-lang.org/t/add-file-info-methods-to-path/6781/1

[ysbaddaden]

I thought I had approved this PR already.

Though there should just be a few fixes to use the non deprecated calls then fix/upgrade the markd shard