Links: Allow '/' in link syntax to make it easy for users to copy-paste URLs from address bar when creating links in source mode

Today, if users are using the source-mode for editing pages, then linking to pages is quite cumbersome as they have to change the '/' to '.' This becomes more so cumbersome if the page-path is 3 or 4 levels deep. Many times, users forget to change one of the slashes, so they come have to preview and come back and edit the link multiple times over.

This is more-so an issue for those users who prefer the source mode over wysiwyg mode.

The best fix for this problem, I believe, is to support '/' in links natively. So such users can simply copy-paste the link from URL address bar without any problems.