Merge rdoc-6.0.0.beta3.

* It version introduced did you mean? feature for ri command:
    https://github.com/ruby/rdoc/pull/533
  * Removed obbsoleted ruby_token.rbb.
    [Bug #13990][ruby-core:83180]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60146 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/rdoc/test_rdoc_markdown.rb

@@ -973,6 +973,14 @@ and an extra note.[^2]
     assert_equal '<b>_emphasis_</b>', @parser.strong('_emphasis_')
   end
 
+  def test_code_fence_with_unintended_array
+    doc = parse '```<ruby>```'
+
+    expected = doc(verb('<ruby>'))
+
+    assert_equal expected, doc
+  end
+
   def parse text
     @parser.parse text
   end