Images with spaces in filename don't work with drag-drop

[krukow]

Drag drop works very well for images (only the #5 snag). If filename of the image contains spaces, however, it doesn't:

[cschleiden]

Yes, we need to escape the filename when inserting, like:

https://markdown-it.github.io/#md3=%7B%22source%22%3A%22%5Blink%5D%28http%3A%2F%2Fwww.bing.com%2F%5C%5C%20test%2F%29%5Cn%5Cn%5Blink%5D%28http%3A%2F%2Fwww.bing.com%2F%20test%2F%29%22%2C%22defaults%22%3A%7B%22html%22%3Afalse%2C%22xhtmlOut%22%3Afalse%2C%22breaks%22%3Afalse%2C%22langPrefix%22%3A%22language-%22%2C%22linkify%22%3Atrue%2C%22typographer%22%3Atrue%2C%22_highlight%22%3Atrue%2C%22_strict%22%3Afalse%2C%22_view%22%3A%22html%22%7D%7D