implemented Rrf Instruction (#21)

Co-authored-by: Darkress <30271678+DarkressX@users.noreply.github.com>
Reviewed-on: darkress/pic16f84-sim#21

de/darkress/pic16f84sim/decoder/CommandDecoder.java

@@ -29,8 +29,7 @@ public class CommandDecoder
             case 0xD00:
                 return new Rlf(input);
             case 0xC00:
-                //rrf();
-                break;
+                return new Rrf(input);
             case 0x200:
                 //subwf();
                 break;