ParsedConstantDefinitions doesn’t support fully qualified constants about packwerk

[tomstuart]

Things have changed since I opened the original issue in June.

The good news is that Packwerk::Node.constant_name (née #const_name) is now aware of fully-qualified constant names:

>> Packwerk::Node.constant_name(Parser::CurrentRuby.parse('::HELLO'))
=> "::HELLO"

>> Packwerk::Node.constant_name(Parser::CurrentRuby.parse('HELLO'))
=> "HELLO"

The bad news is that ParsedConstantDefinitions#collect_local_definitions doesn’t know what to do with this:

>> definitions = Packwerk::ParsedConstantDefinitions.new(
     root_node: Parser::CurrentRuby.parse('module Sales; ::HELLO = "World"; end')
   )
=> #<Packwerk::ParsedConstantDefinitions
    @local_definitions=
     {"::Sales"=>#<struct Packwerk::Node::Location line=1, column=7>,
      "::Sales::::HELLO"=>#<struct Packwerk::Node::Location line=1, column=16>}>

>> definitions.local_reference?('HELLO')
=> false # should be true

>> definitions.local_reference?('Sales::HELLO')
=> false # correct, but for the wrong reason

You can see that @local_definitions now contains an erroneous entry for ::Sales::::HELLO, formed by naively joining 'Sales' and '::HELLO' with '::'. We still have no test coverage for this so it’s not affecting the build, but it’s obviously wrong behaviour that will bite anyone who tries to use fully-qualified constants.