Confusing error message when using a File that wasn't built from a bookmark.

[pschuegr]

When you pass in a File that you don't have a bookmark for to startAccessingSecurityScopedResource, the error message says

expected file argument to be string

When the actual problem is that you don't have a bookmark for this file. Since the API allows arbitrary files to be passed in, it would be great if the error message was better for this situation.

I'm not familiar with Swift so I don't really want to fix it myself, but I'm happy to send a PR to update the documentation if you don't want to fix this.

Thanks! Super happy I found this plugin.

[stephane-archer]

@sbhamad, it is unclear why you need to create a bookmark from a file, resolve it to get another file (what's special about this one?), and then pass it to startAccessingSecurityScopedResource.