Sort files which is the entries of file completion
Sort files which is the entries of file completion

Since macOS have introduced APFS, the order of Readdirnames or Readdir
of *os.File has been changed.
To provide consistent experience, the order should be always alphabetical.

According to <https://developer.apple.com/library/content/documentation/FileManagement/Conceptual/APFS_Guide/FAQ/FAQ.html>:
	  Calling readdir(2) on a directory in APFS returns filenames
	  in hash order, whereas HFS+ returns filenames in
	  lexicographical order.

elpinal/coco3