Add line/column information consistently to every parser message.

It would be useful to have clear parser errors which have the position (line and column) printed.

Now for some errors there is information of where the error happened:

`Unterminated string literal at Line: {}, Col: {}`

For others, there isn't:

`Unexpected EOF while in a multi-line comment`

I think this would be a "good first issue" to work on, maybe I find some time to work on this soon.

Start by locating the parser error messages, including “Unterminated string literal” and “Unexpected EOF while in a multi-line comment,” and inspect how line and column positions are currently attached. Audit the remaining parser messages and determine the tests covering them. Done means every parser message consistently includes line and column information.

Written by the indexing model from the issue text.