def visit_root(node)
      @enabled = matcher.match(File.basename(node.file)) ? true : false
    end
def visit_root(node)
      @enabled = matcher.match(File.basename(node.file)) ? true : false
    end
Enables the linter if the tree is for the right file type.

 @param [HamlLint::Tree::RootNode] the root of a syntax tree
 @return [true, false] whether the linter is enabled for the tree