Bump RDoc to 7.0.0

This improves several enhancements to the Aliki theme. And since Aliki
also became the default theme, we don't need to specify the generator name
anymore.

Author: st0012

.rdoc_options

@@ -12,8 +12,6 @@ exclude:
 - \.gemspec\z
 - lib/set/subclass_compatible.rb
 
-generator_name: aliki
-
 autolink_excluded_words:
 - Box
 - Class

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                6.17.0  https://github.com/ruby/rdoc
+rdoc                7.0.0   https://github.com/ruby/rdoc
 win32ole            1.9.2   https://github.com/ruby/win32ole
 irb                 1.16.0  https://github.com/ruby/irb
 reline              0.6.3   https://github.com/ruby/reline