- add support for seq -s <separator>

include/usage.h

@@ -3594,12 +3594,13 @@
      "\nOther options are silently ignored; -oi is implied" \
 
 #define seq_trivial_usage \
-       "[-w] [first [increment]] last"
+       "[-w] [-s separator] [first [increment]] last"
 #define seq_full_usage "\n\n" \
        "Print numbers from FIRST to LAST, in steps of INCREMENT.\n" \
        "FIRST, INCREMENT default to 1\n" \
      "\nArguments:" \
-     "\n       -w          Pad to last with leading zeros" \
+     "\n	-w          Pad to last with leading zeros" \
+     "\n	-s <string> Use string separator" \
      "\n	LAST" \
      "\n	FIRST LAST" \
      "\n	FIRST INCREMENT LAST" \