@ ProgramNode (location: (1,0)-(1,6))
├── locals: []
└── statements:
    @ StatementsNode (location: (1,0)-(1,6))
    └── body: (length: 1)
        └── @ StringNode (location: (1,0)-(1,6))
            ├── flags: ∅
            ├── opening_loc: (1,0)-(1,6) = "<<~FOO"
            ├── content_loc: (2,0)-(4,0) = "  baz\\\n  qux\n"
            ├── closing_loc: (4,0)-(5,0) = "FOO\n"
            └── unescaped: "baz  qux\n"
