(https://github.com/ruby/rdoc/pull/1144)

* Add a new ruby parser RDoc::Parser::PrismRuby

* Add a new ruby parser testcase independent from parser's internal implementation

* unknown meta method

* Use MethodSignatureVisitor only to scan params, block_params and calls_super

* Add calls_super test

* Drop ruby 2.6. Prism requires ruby >= 2.7

* Remove duplicated documentation comment from prism_ruby.rb

* Add test for wrong argument passed to metaprogramming method

* Rename visit_call_[DSL_METHOD_NAME] to make it distinguishable from visit_[NODE_TYPE]_node

* Method receiver switch of true/false/nil to a case statement

* Extract common part of add_method(by def keyword) and add meta_comment method

* Reuse consecutive comments array when collecting comments

* Simplify DSL call_node handling

* Refactor extracting method visibility arguments

https://github.com/ruby/rdoc/commit/fde99f1be6

(https://github.com/ruby/rdoc/pull/1118)

* Drop reimplementation of Ripper lex state

This code was for ruby 2.4 compatibility, but rdoc dropped support for
ruby 2.4 about three years ago, in f480b970c.  This code was almost half
of the lines of code in rdoc/parser/ripper_state_lex.

* Remove unused Ripper constants and const_defined?

This was mostly copied from the diff in @st0012's PR comment.  The
remaining constants have been updated to get their value directly from
Ripper.

Co-authored-by: Stan Lo <stan001212@gmail.com>

* Use Ripper::EXPR_LABEL directly

Since this is only used from outside RipperStateLex, there's no longer
any benefit to using the indirect reference rather than just going
straight to Ripper.

---------

https://github.com/ruby/rdoc/commit/dd8c216263

Co-authored-by: Stan Lo <stan001212@gmail.com>

Attribute readers and writers can be marked as `:nodoc` to keep them
undocumented:

```ruby
attr_reader :name # :nodoc:
```

For aliases this behaviour should be the same:

```ruby
alias_method :old :new # :nodoc:
```

https://github.com/ruby/rdoc/commit/30f14e8271

Even for singleton class definition such as `class << self` that
shares the same container with the outer scope, its visibility is
separated and set to `public` by default.

https://github.com/ruby/rdoc/commit/baf26363b9

Each singleton method definition of the form `def recv.method` has
visibility separate from the outer scope and is set to `public` by
default.

https://github.com/ruby/rdoc/commit/810913a7ea

https://github.com/ruby/rdoc/commit/e4c90340d0

Fix https://github.com/ruby/rdoc/pull/995

https://github.com/ruby/rdoc/commit/adfa7db5b9

The calls to require prevent the class from being documented.

https://github.com/ruby/rdoc/commit/76283fc42e