Update man pages to include ext4 in the synposis, instead of just "ext2/ext3"

The e2fsprogs programs have historically just said that they operate
on ext2 and ext3 file system in their man pages.  Update them to say
that they also operate on ext4 file systems.

Addresses-Launchpad-bug: #381854

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
9 files changed