Fixed missing comma in mruby/mirb usage.

mrbgems/mruby-bin-mirb/tools/mirb/mirb.c

@@ -230,7 +230,7 @@ usage(const char *name)
 {
   static const char *const usage_msg[] = {
   "switches:",
-  "-d           set $DEBUG to true (same as `mruby -d`)"
+  "-d           set $DEBUG to true (same as `mruby -d`)",
   "-r library   same as `mruby -r`",
   "-v           print version number, then run in verbose mode",
   "--verbose    run in verbose mode",

mrbgems/mruby-bin-mruby/tools/mruby/mruby.c

@@ -41,7 +41,7 @@ usage(const char *name)
   "switches:",
   "-b           load and execute RiteBinary (mrb) file",
   "-c           check syntax only",
-  "-d           set debugging flags (set $DEBUG to true)"
+  "-d           set debugging flags (set $DEBUG to true)",
   "-e 'command' one line of script",
   "-r library   load the library before executing your script",
   "-v           print version number, then run in verbose mode",