Add EXPR_ARG to condition of postfix if

Author: aycabta

lib/rdoc/parser/ripper_state_lex.rb

@@ -101,7 +101,7 @@ def on_kw(tok, data)
         @continue = true
         @in_fname = true
       when 'if', 'unless', 'while', 'until'
-        if ((EXPR_END | EXPR_ENDARG | EXPR_ENDFN | EXPR_CMDARG) & @lex_state) != 0 # postfix if
+        if ((EXPR_END | EXPR_ENDARG | EXPR_ENDFN | EXPR_ARG | EXPR_CMDARG) & @lex_state) != 0 # postfix if
           @lex_state = EXPR_BEG | EXPR_LABEL
         else
           @lex_state = EXPR_BEG