Add fib.ir example and update argument documentation

examples/fib.ir

@@ -0,0 +1,39 @@
+preamble {
+    $all_players = selector a
+}
+
+function main {
+    preamble {
+        $x = define i32
+        $y = define i32
+        $old_x = define i32
+        $counter = define i32
+        extern
+    }
+
+    entry:
+    $x = 0
+    $y = 1
+    $counter = 1
+    branch :loop
+
+    loop:
+    $msg = text
+    text_append $msg, "fib("
+    text_append $msg, $counter
+    text_append $msg, ") = "
+    text_append $msg, $x
+    text_send $msg, $all_players
+    set_command_block :post_tick
+
+    post_tick:
+    clear_command_block
+    $counter += 1
+    $old_x = $x
+    $x = $y
+    $y += $old_x
+    rangebr $x, 0, NULL, :loop, :end
+
+    end:
+    ret
+}

ir_main.py

@@ -45,14 +45,14 @@ def main(args):
 
 if __name__ == '__main__':
     parser = argparse.ArgumentParser()
-    parser.add_argument('file', help="ASM File", type=argparse.FileType('r'))
+    parser.add_argument('file', help="Command IR File", type=argparse.FileType('r'))
     parser.add_argument('--world-dir', help="World Directory")
     parser.add_argument('--as-zip', action='store_true', help="Write datapack as zip file")
     parser.add_argument('--namespace', help="Function namespace", default='ir_generated')
     parser.add_argument('--rem-existing', help="Remove existing functions in namespace",
                         action='store_true')
     parser.add_argument('--debug', action='store_true', help="Enable debug output")
-    parser.add_argument('--dump-ir', action='store_true', help="Dump CMD IR output")
+    parser.add_argument('--dump-ir', action='store_true', help="Dump Command IR output")
     parser.add_argument('--gen-cleanup', action='store_true', help="Generate cleanup function")
     parser.add_argument('--place-location', help="Location to place command blocks", required=True)
     parser.add_argument('--spawn-location', default='~ ~2 ~',