[ruby/psych] fix typo

https://github.com/ruby/psych/commit/ebb0cbded1

test/psych/test_scalar_scanner.rb

@@ -130,8 +130,8 @@ module Psych
       assert_equal 123_456_789, ss.tokenize('1_2,3,4_5,6_789')
 
       assert_equal 1, ss.tokenize('1')
-      assert_equal 1 ss.tokenize('+1')
-      assert_equal -1 ss.tokenize('-1')
+      assert_equal 1, ss.tokenize('+1')
+      assert_equal -1, ss.tokenize('-1')
 
       assert_equal 0b010101010, ss.tokenize('0b010101010')
       assert_equal 0b010101010, ss.tokenize('0b0,1_0,1_,0,1_01,0')