epoll_ctl.2: Use the term "interest list" consistently

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man2/epoll_ctl.2

@@ -26,7 +26,8 @@ epoll_ctl \- control interface for an epoll file descriptor
 .BI "int epoll_ctl(int " epfd ", int " op ", int " fd \
 ", struct epoll_event *" event );
 .SH DESCRIPTION
-This system call performs control operations on the
+This system call is used to add, modify, or remove
+entries in the interest list of the
 .BR epoll (7)
 instance
 referred to by the file descriptor
@@ -41,12 +42,9 @@ Valid values for the
 argument are:
 .TP
 .B EPOLL_CTL_ADD
-Register the target file descriptor
+Add
 .I fd
-on the
-.B epoll
-instance referred to by the file descriptor
-.I epfd
+to the interest list
 and associate the event
 .I event
 with the internal file linked to
@@ -55,16 +53,14 @@ with the internal file linked to
 .B EPOLL_CTL_MOD
 Change the event
 .I event
-associated with the target file descriptor
-.IR fd .
+associated with
+.IR fd
+in the interest list.
 .TP
 .B EPOLL_CTL_DEL
 Remove (deregister) the target file descriptor
 .I fd
-from the
-.B epoll
-instance referred to by
-.IR epfd .
+from the interest list.
 The
 .I event
 is ignored and can be NULL (but see BUGS below).