[Finder] Add info about possibilities offered by SplFileInfo
minor #12059 [Finder] Add info about possibilities offered by SplFileInfo (ywarnier)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #12059).

Discussion
----------

[Finder] Add info about possibilities offered by SplFileInfo

Minor documentation improvement

Commits
-------

b2219cf [Finder] Add info about possibilities offered by SplFileInfo