Don't duplicate line numbers when annotating internal errors

Closes 5463

The `annotate_snippets` crate adds line number and column info to the
output, so we don't need to append the line number to the `origin`.

Previously, internal errors would be output with the line number twice.
See how 478 is duplicated in the example below.

```
error[internal]: line formatted, but exceeded maximum width
   --> /path/to/file.rs:478:478:101
```

Now the line number is not duplicated.

```
error[internal]: line formatted, but exceeded maximum width
   --> /path/to/file.rs:478:101
```

Author: ytmimi

src/format_report_formatter.rs

@@ -78,7 +78,7 @@ impl<'a> Display for FormatReportFormatter<'a> {
                     None
                 };
 
-                let origin = format!("{}:{}", file, error.line);
+                let origin = file.to_string();
                 let slice = Slice {
                     source: &error.line_buffer.clone(),
                     line_start: error.line,