Invalid Source Line in diff error message when using variable with newline

[fabricereix]

The following textual response

line1
line2
line3
line4

can be tested with the multiline body in Hurl.:

1     GET http://localhost:8000/test
2     HTTP 200
3    ```
4    line1
5    line2
6    line3
7    line4
8    ```

If LINE4 is returned by the server (instead of line4), we have the following error message (as expected):

    --> test.hurl:5:1
    |
    | GET http://localhost:8000/test
    | ...
  7 | line4
    |   -line4
    |   +LINE4
    |

The invalid source line can occur when the expected body contains variables with newline value.
For example:

1  GET http://localhost:8000/test
2  [Options]
3  variable: newline=\n
4  HTTP 200
5  ```
6  line1
7  line2{{newline}}line3
8  line4
9  ```

The error has now an invalid source line:

  --> /tmp/test.hurl:9:1
  |
  | GET http://localhost:8000/test
  | ...
9 | ```
  |   -line4
  |   +LINE4
  |

```

[fabricereix]

The challenge here is to keep original source information. We may have to introduce a kind of source map.