(#22180) Fix broken rdoc1 features

There were a number of rdoc1 features (tracking of included, required
modules, realized virtual resources, all resources when :document_all
setting is true, and global variables) which had not been functioning
due to the parser wrapping statements in
Puppet::Parser::AST::BlockExpression instances now rather than
Puppet::Parser::AST::Array instances.

This is now fixed so that these areas are documented when using rdoc1.
Only included classes is documented in rdoc2, however.  Documenting the
remaining elements would require writing a new renderer.