Jean Boussier 8d05047d72 Add a Module#const_added callback
[Feature #17881]

Works similarly to `method_added` but for constants.

```ruby
Foo::BAR = 42 # call Foo.const_added(:FOO)
class Foo::Baz; end # call Foo.const_added(:Baz)
Foo.autoload(:Something, "path") # call Foo.const_added(:Something)
```
2022-01-14 11:30:07 +01:00
..
2022-01-14 11:30:07 +01:00