BRAKING CHANGE: Add location to AST object

[kamiazya]

What was a problem

The input dot language cannot specify the location in the character string, and the range of utilization of AST is limited.

How this PR fixes the problem

Include the location of the AST object in the string as an AST attribute.

const ast = AST.parse(`
  digraph example {
    node1 [
      label = "My Node",
    ]
  }
`);

console.log(inspect(ast, false, Infinity));
// {
//   type: 'graph',
//   id: {
//     type: 'literal',
//     value: 'example',
//     quoted: false,
//     location: {
//       start: { offset: 11, line: 2, column: 11 },
//       end: { offset: 18, line: 2, column: 18 }
//     }
//   },
//   directed: true,
//   strict: false,
//   body: [
//     {
//       type: 'node',
//       id: {
//         type: 'literal',
//         value: 'node1',
//         quoted: false,
//         location: {
//           start: { offset: 25, line: 3, column: 5 },
//           end: { offset: 30, line: 3, column: 10 }
//         }
//       },
//       attributes: [
//         {
//           type: 'attribute',
//           key: {
//             type: 'literal',
//             value: 'label',
//             quoted: false,
//             location: {
//               start: { offset: 39, line: 4, column: 7 },
//               end: { offset: 44, line: 4, column: 12 }
//             }
//           },
//           value: {
//             type: 'literal',
//             value: 'My Node',
//             quoted: true,
//             location: {
//               start: { offset: 47, line: 4, column: 15 },
//               end: { offset: 56, line: 4, column: 24 }
//             }
//           },
//           location: {
//             start: { offset: 39, line: 4, column: 7 },
//             end: { offset: 57, line: 4, column: 25 }
//           }
//         }
//       ],
//       location: {
//         start: { offset: 25, line: 3, column: 5 },
//         end: { offset: 66, line: 6, column: 3 }
//       }
//     }
//   ],
//   location: {
//     start: { offset: 0, line: 1, column: 1 },
//     end: { offset: 68, line: 7, column: 1 }
//   }
// }

Check lists (check x in [ ] of list items)

• Test passed
• Coding style (indentation, etc)