patch 9.0.0008: cannot specify the variable name for "xxd -i"

Problem:    Cannot specify the variable name for "xxd -i".
Solution:   Add the "-name" argument. (David Gow, closes #10599)
diff --git a/runtime/doc/xxd.1 b/runtime/doc/xxd.1
index fb0ac44..b0cb183 100644
--- a/runtime/doc/xxd.1
+++ b/runtime/doc/xxd.1
@@ -113,6 +113,10 @@
 .RI  < len >
 octets.
 .TP
+.I "\-n name " | " \-name name"
+Override the variable name output when \-i is used. The array is named
+\fIname\fP and the length is named \fIname\fP_len.
+.TP
 .I \-o offset
 Add
 .RI < offset >