A bug in man page

[Qijia Liu]

Hello,
The man page says that if the --newer option takes a file instead of date, that 
file’s ctime is used as the date. However, 
https://www.gnu.org/software/tar/manual/tar.html 
<https://www.gnu.org/software/tar/manual/tar.html> says the file’s mtime should 
be used. Please check that.
Sincerely,
Liumeo