Show line numbers in JS input to match error line:column

[treblereel]

Summary
The compiler output references line:column for errors and warnings, but the input editor does not display line numbers. This makes it difficult to locate the referenced positions.

Problem

Diagnostics report positions as line:column.

The input editor lacks a line-number gutter.

Pasted snippets often do not match original file line numbers (e.g., when the source file also contains HTML/CSS), causing confusion.

[kapyaar]

Thanks for creating this as an issue. Since we are talking enhancements, few minor thoughts.

1. Everytime compile is performed, It would be nice to clear the output area. When the output is shown, it is a lot more clearer as to the compile process being complete.
2. When clicking on the "Copy code to Clipboard" (really awesome feature), change the text to "Copied" or change the color or something, to indicate. :)

[treblereel]

@kapyaar sounds nice. I think it’s worth a separate issues