[ruby/rdoc] Support linking #==

See related commits:

- ebc66662 for #===
- 4943d208 for #[], #[]=, #<<, and #>>

https://github.com/ruby/rdoc/commit/8e47f7840a

lib/rdoc/cross_reference.rb

@@ -19,7 +19,7 @@ class RDoc::CrossReference
   #
   # See CLASS_REGEXP_STR
 
-  METHOD_REGEXP_STR = '([a-z]\w*[!?=]?|%|===|\[\]=?|<<|>>|\+@|-@|-|\+|\*)(?:\([\w.+*/=<>-]*\))?'
+  METHOD_REGEXP_STR = '([a-z]\w*[!?=]?|%|===?|\[\]=?|<<|>>|\+@|-@|-|\+|\*)(?:\([\w.+*/=<>-]*\))?'
 
   ##
   # Regular expressions matching text that should potentially have

test/rdoc/test_rdoc_cross_reference.rb

@@ -20,7 +20,7 @@ class TestRDocCrossReference < XrefTestCase
   def test_METHOD_REGEXP_STR
     re = /#{RDoc::CrossReference::METHOD_REGEXP_STR}/
 
-    %w'=== [] []= << >>'.each do |x|
+    %w'== === [] []= << >>'.each do |x|
       re =~ x
       assert_equal x, $&
     end