Add cur extension for url-loader

[yitzchak]

References

https://developer.mozilla.org/en-US/docs/Web/CSS/cursor

Code changes

CSS cursor attribute allows multiple files as fallbacks including Windows cursors (.cur), PNG, etc. Some packages in npm come packaged with .cur files and therefore will fail in webpack during installation.

User-facing changes

None

Backwards-incompatible changes

None

[jupyterlab-dev-mode]

Thanks for making a pull request to JupyterLab!

To try out this branch on binder, follow this link:

[telamonian]

Though I for one have never seen a .cur file, this does appear to be kosher. I'll pull this in, unless anyone has objections.

@yitzchak Out of curiosity, what's an example of a package that will cause webpack to fail without a cur loader?

[yitzchak]

@telamonian Thanks! The package that I currently have the issue with is kekule. Working on a widget version.

[blink1073]

Congratulations on your first contribution to JupyterLab @yitzchak!

[yitzchak]

Thanks @blink1073!