Fix -yy documentation

* strace.c (usage): Fix description of -yy option.
* strace.1: Likewise.
diff --git a/strace.1 b/strace.1
index 429cdfc..b7dddc0 100644
--- a/strace.1
+++ b/strace.1
@@ -325,7 +325,7 @@
 Print paths associated with file descriptor arguments.
 .TP
 .B \-yy
-Print ip:port pairs associated with socket file descriptors.
+Print protocol specific information associated with socket file descriptors.
 .TP
 .BI "\-a " column
 Align return values in a specific column (default column 40).