Update README.md

Author: schlessera

README.md

@@ -80,6 +80,7 @@ wp media import <file>... [--post_id=<post_id>] [--title=<title>] [--caption=<ca
 
 	[--skip-copy]
 		If set, media files (local only) are imported to the library but not moved on disk.
+		File names will not be run through wp_unique_filename() with this set.
 
 	[--preserve-filetime]
 		Use the file modified time as the post published & modified dates.