Enhance `showPosition()` to Accurately Display Error Position by Line Number

### Description

Preserve new-lines in templates when showing the position of parsing-errors.

### Current behavior

#### Input

```hbs
{{#if}
HELLO
{{/if}}
```

#### Error

```
Parse error on line 1:
{{#if} HELLO{{/if}}
-----^
```

https://handlebarsjs.com/playground.html#format=1¤tExample=%7B%22template%22%3A%22%7B%7B%23if%7D%5Cn%20%20HELLO%5Cn%7B%7B%2Fif%7D%7D%22%2C%22partials%22%3A%5B%5D%2C%22input%22%3A%22%7B%7D%5Cn%22%2C%22output%22%3A%22Yehuda%20KATZ%5Cn%22%2C%22preparationScript%22%3A%22%22%2C%22handlebarsVersion%22%3A%224.7.8%22%7D

### Expected behavior

```hbs
{{#if}
HELLO
{{/if}}
```

#### Error

```
Parse error on line 1:
{{#if}
----^
HELLO
{{/if}}
```

### Original issues

@jaylinski can we enhance `showPosition()` ??
**to Ensures that the ----^ indicator accurately reflects the error position on the relevant line, rather than defaulting to the last line:**

For more visit: https://github.com/zaach/jison/issues/406

Start by locating showPosition() in the JavaScript parser and reproduce the template example from the issue. Compare the current and expected parse-error output, then verify that newlines are preserved and the caret points to the error position on the relevant line.

Written by the indexing model from the issue text.