Fix backward compatibility since RDoc 6.13.0

Some methods have been removed in
ruby/rdoc#1315.

Author: alexisbernard

lib/rdoc/generator/template/rorvswild/_sidebar_extends.rhtml

@@ -3,7 +3,7 @@
     <h3>Extended With Modules</h3>
 
     <ul class="link-list">
-      <%- klass.each_extend do |ext| -%>
+      <%- klass.extends.each do |ext| -%>
     <%- unless String === ext.module then -%>
       <li><a class="extend" href="<%= klass.aref_to ext.module.path %>"><%= ext.module.full_name %></a>
     <%- else -%>

lib/rdoc/generator/template/rorvswild/_sidebar_includes.rhtml

@@ -3,7 +3,7 @@
     <h3>Included Modules</h3>
 
     <ul class="link-list">
-    <%- klass.each_include do |inc| -%>
+    <%- klass.includes.each do |inc| -%>
     <%- unless String === inc.module then -%>
       <li><a class="include" href="<%= klass.aref_to inc.module.path %>"><%= inc.module.full_name %></a>
     <%- else -%>

lib/rorvswild_theme_rdoc.rb

@@ -1,4 +1,5 @@
 require "rorvswild_theme_rdoc/patches/rdoc"
+require "rorvswild_theme_rdoc/patches/rdoc_before_6.13.0"
 
 module RorVsWildThemeRdoc
 end

lib/rorvswild_theme_rdoc/patches/rdoc_before_6.13.0.rb

@@ -0,0 +1,10 @@
+if RDoc::VERSION < "6.13.0"
+  # https://github.com/ruby/rdoc/pull/1315
+  module RDoc
+    class NormalClass
+      attr_reader :includes
+      attr_reader :extends
+      attr_reader :constants
+    end
+  end
+end