https://github.com/ruby/rdoc/commit/f7dd147a8c

https://github.com/ruby/rdoc/commit/2161157205

https://github.com/ruby/rdoc/commit/0d10f460eb

This allows RDoc to better generate documentation for methods
following the Ruby core documentation guide (which omits aliases
in call-seq in most cases).  This makes documentation for methods
defined in C more similar to methods defined in Ruby.  For methods
defined in Ruby, the method description of the aliased method is
already not used (you have to explicitly document the alias to
use it).

Internally, this adds AnyMethod#has_call_seq? and #skip_description?,
and updates Darkfish to:

* only show the method name if there is a call-seq for the method,
  but the call-seq omits the method
* to omit the method description if the method is an alias or has
  aliases and has a call-seq that does not include the method

See discussion in https://github.com/ruby/ruby/pull/7316 for
details.

https://github.com/ruby/rdoc/commit/e3688de49b

This commit improves the behavior of showing the "toggle source" element on mouseover.

For example, when a method has one more signatures by using `:call-seq:`,

```ruby
# :call-seq:
#   foo {|element| ... } -> self
#   foo -> new_enumeration
def foo
end
```

The current CSS doesn't show "toggle source" even when hovering the second signature `foo -> new_enumeration`.
But this change will show "toggle source" always when hovering over any signature.

For details about the `.method-header` element, see `lib/rdoc/generator/template/darkfish/class.rhtml`:
https://github.com/ruby/rdoc/blob/0e060c69f51ec4a877e5cde69b31d47eaeb2a2b9/lib/rdoc/generator/template/darkfish/class.rhtml#L101-L124

For example, see https://docs.ruby-lang.org/en/3.2/Array.html#method-i-delete

https://github.com/ruby/rdoc/commit/663edc807c

https://github.com/ruby/rdoc/commit/db62e47df2

https://github.com/ruby/rdoc/commit/76192a280d

https://github.com/ruby/rdoc/commit/4b68c0728a

- Use a smaller font size for the toggle symbol. (Currently, it seems a little too large)
- Use the child combinator (`>`) to unify selectors.
- Use `margin-left` instead of whitespace within the `content` property.
- Use `::` instead of outdated `:` for the pseudo-element symbol.
  (See https://developer.mozilla.org/en-US/docs/Web/CSS/::before)

https://github.com/ruby/rdoc/commit/61ce0a7d75