[DOC] Use Aliki as the documentation website theme (ruby#15319)

Use Aliki as the documentation website theme

Author: st0012

.rdoc_options

@@ -11,6 +11,8 @@ rdoc_include:
 exclude:
 - \.gemspec\z
 
+generator_name: aliki
+
 autolink_excluded_words:
 - Class
 - Method
@@ -23,3 +25,16 @@ autolink_excluded_words:
 - YJIT
 
 canonical_root: https://docs.ruby-lang.org/en/master
+
+footer_content:
+  Ruby:
+    Documentation: index.html
+    Official Website: https://www.ruby-lang.org/
+    Playground: https://ruby.github.io/play-ruby/
+  Resources:
+    GitHub: https://github.com/ruby/ruby
+    Issue Tracker: https://bugs.ruby-lang.org/projects/ruby-master/issues
+    RubyGems: https://rubygems.org/
+  Community:
+    X: https://x.com/rubylangorg
+

gems/bundled_gems

@@ -39,7 +39,7 @@ ostruct             0.6.3   https://github.com/ruby/ostruct
 pstore              0.2.0   https://github.com/ruby/pstore
 benchmark           0.5.0   https://github.com/ruby/benchmark
 logger              1.7.0   https://github.com/ruby/logger
-rdoc                6.15.1  https://github.com/ruby/rdoc
+rdoc                6.16.0  https://github.com/ruby/rdoc
 win32ole            1.9.2   https://github.com/ruby/win32ole
 irb                 1.15.3  https://github.com/ruby/irb
 reline              0.6.3   https://github.com/ruby/reline