Revert "[ruby/rdoc] fix: C variables should never show up in Ancestors tree"

This reverts commit 2923f42.

https://github.com/ruby/actions/actions/runs/12108034481/job/33755653615#step:23:1031

```
/home/runner/work/actions/actions/snapshot-master/lib/rdoc/code_object.rb:322:in 'RDoc::CodeObject#parent': undefined method 'find_class_or_module' for nil (NoMethodError)
	from /home/runner/work/actions/actions/snapshot-master/lib/rdoc/code_object/class_module.rb:342:in 'RDoc::ClassModule#marshal_dump'
	from /home/runner/work/actions/actions/snapshot-master/lib/rdoc/store.rb:878:in 'Marshal.dump'
	from /home/runner/work/actions/actions/snapshot-master/lib/rdoc/store.rb:878:in 'block in RDoc::Store#save_class'
	from /home/runner/work/actions/actions/snapshot-master/lib/rdoc/store.rb:877:in 'IO.open'
	from /home/runner/work/actions/actions/snapshot-master/lib/rdoc/store.rb:877:in 'RDoc::Store#save_class'
	from /home/runner/work/actions/actions/snapshot-master/lib/rdoc/store.rb:763:in 'block in RDoc::Store#save'
	from /home/runner/work/actions/actions/snapshot-master/lib/rdoc/store.rb:762:in 'Array#each'
	from /home/runner/work/actions/actions/snapshot-master/lib/rdoc/store.rb:762:in 'RDoc::Store#save'
	from /home/runner/work/actions/actions/snapshot-master/lib/rdoc/generator/ri.rb:27:in 'RDoc::Generator::RI#generate'
	from /home/runner/work/actions/actions/snapshot-master/lib/rdoc/rdoc.rb:528:in 'block in RDoc::RDoc#generate'
	from /home/runner/work/actions/actions/snapshot-master/lib/rdoc/rdoc.rb:522:in 'Dir.chdir'
	from /home/runner/work/actions/actions/snapshot-master/lib/rdoc/rdoc.rb:522:in 'RDoc::RDoc#generate'
	from /home/runner/work/actions/actions/snapshot-master/lib/rdoc/rdoc.rb:501:in 'RDoc::RDoc#document'
	from ./tool/rdoc-srcdir:27:in '<main>'
```

Author: hsbt

lib/rdoc/rdoc.rb

@@ -415,8 +415,6 @@ def parse_files files
       parse_file filename
     end.compact
 
-    @store.resolve_c_superclasses
-
     @stats.done_adding
     @options = original_options
 

lib/rdoc/store.rb

@@ -197,18 +197,6 @@ def add_file absolute_name, relative_name: absolute_name, parser: nil
     top_level
   end
 
-  ##
-  # Make sure any references to C variable names are resolved to the corresponding class.
-  #
-
-  def resolve_c_superclasses
-    @classes_hash.each_value do |klass|
-      if klass.superclass.is_a?(String) && (candidate = find_c_enclosure(klass.superclass))
-        klass.superclass = candidate
-      end
-    end
-  end
-
   ##
   # Sets the parser of +absolute_name+, unless it from a source code file.
 

test/rdoc/test_rdoc_store.rb

@@ -281,26 +281,6 @@ def test_find_c_enclosure_from_cache_legacy
     assert_nil @s.find_c_enclosure('cObject')
   end
 
-  def test_resolve_c_superclasses
-    # first parse a child that references an unknown parent
-    c_file1 = @s.add_file 'ext1.c'
-    c_file1.add_class RDoc::NormalClass, 'Child', 'cExternParent'
-
-    # then parse the parent and register the C variable name as a C enclosure
-    c_file2 = @s.add_file 'ext2.c'
-    parent = c_file2.add_class RDoc::NormalClass, 'Parent', 'rb_cObject'
-
-    @s.add_c_enclosure('cExternParent', parent)
-
-    # at this point, the child's superclass is still the name of the C variable
-    assert_equal("cExternParent", @s.classes_hash['Child'].superclass)
-
-    @s.resolve_c_superclasses
-
-    # now the ancestor tree correctly references the NormalClass objects
-    assert_equal(parent, @s.classes_hash['Child'].superclass)
-  end
-
   def test_find_class_named
     assert_equal @c1, @store.find_class_named('C1')