Followup of #1800: remove unused code/comment (#1801)

Author: tompng

lib/rdoc/code_object/context.rb

@@ -108,7 +108,7 @@ class RDoc::Context < RDoc::CodeObject
   attr_reader :constants_hash
 
   ##
-  # Creates an unnamed empty context with public current visibility
+  # Creates an unnamed empty context
 
   def initialize
     super

lib/rdoc/parser/ruby.rb

@@ -629,7 +629,6 @@ def add_alias_method(old_name, new_name, line_no)
     handle_code_object_directives(@container, directives) if directives
     return if document_suppressed?
 
-    visibility = @container.find_method(old_name, @singleton)&.visibility || :public
     a = RDoc::Alias.new(old_name, new_name, comment, singleton: @singleton)
     handle_modifier_directive(a, line_no)
     a.store = @store

test/rdoc/rdoc_stats_test.rb

@@ -83,8 +83,6 @@ def test_report_constant
   end
 
   def test_report_constant_alias
-    mod = @tl.add_module RDoc::NormalModule, 'M'
-
     c = @tl.add_class RDoc::NormalClass, 'C'
 
     ca = RDoc::Constant.new 'CA', nil, nil