(https://github.com/ruby/rdoc/pull/1137)

This is an attempt to utilize RuboCop further.
RuboCop was added in https://github.com/ruby/rdoc/commit/9262fdd43a3a
but only a few rules have been enabled.
I believe we can utilize RuboCop more for better code quality,
especially with Lint cops.
This is the first step to enable other Lint cops.
This commit also exclude some auto generated files.

https://github.com/ruby/rdoc/commit/a53287fce0

(https://github.com/ruby/rdoc/pull/1218)

* Deprecate :main: directive

* Deprecate :title: direcive

* Update documentation

* Remove :main: directive's usage

* Update test cases

* Add '.rdoc_options' to suggested alternatives

https://github.com/ruby/rdoc/commit/e2d4ac9dad

This reverts commit 0fe82ae087130d7f360cc0607be93995cedbdb16.

This reverts commit 2923f42ed7622f6310c63aab4c0abf05402f9a04.

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>'
```

(https://github.com/ruby/rdoc/pull/1217)

If a NormalClass's superclass is a C enclosure, then update the
superclass to point to the RDoc::NormalClass.

This is done in a single pass after all files have been parsed.

Fixes https://github.com/ruby/rdoc/pull/1205.

https://github.com/ruby/rdoc/commit/1ecd9581b1

(https://github.com/ruby/rdoc/pull/1165)

The link is clickable in the terminal and opens the home page in the browser

https://github.com/ruby/rdoc/commit/b7d580afab

Avoids warnings like

```
/path/to/ruby/3.3.4/lib/ruby/gems/3.3.0/gems/rbs-3.4.0/lib/rdoc/discover.rb:10: warning: method redefined; discarding old scan
/path/to/ruby/3.3.4/lib/ruby/gems/3.3.0/gems/rbs-3.5.1/lib/rdoc/discover.rb:10: warning: previous definition of scan was here
```

https://github.com/ruby/rdoc/commit/e47920d8f3

method.
(https://github.com/ruby/rdoc/pull/1135)

* Unify top_level creation in tests

* Remove unnecessary file_name param from Parser.for

It should be always the same as the top_level's absolute_name, so there's
no point of taking it as a separate parameter.

https://github.com/ruby/rdoc/commit/97c497dfbb

This ensures only files from the root directory are chosen, in order to allow a clean build from outside the source directory.

https://github.com/ruby/rdoc/commit/f3b389aa9e