@ ProgramNode (location: (0...10))
├── locals: []
└── statements:
    @ StatementsNode (location: (0...10))
    └── body: (length: 1)
        └── @ StringNode (location: (0...10))
            ├── opening_loc: (0...10) = "<<-HEREDOC"
            ├── content_loc: (11...15) = "\#${\n"
            ├── closing_loc: (15...23) = "HEREDOC\n"
            └── unescaped: "\#${\n"
