Add 'Copy URL' to download context menu

See #1078

doc/changelog.asciidoc

@@ -118,6 +118,7 @@ Added
   show when `:open` is used without any input.
 - New `QUTE_VERSION` variable for userscripts, which can be used to read
   qutebrowser's version.
+- New "Copy URL" entry in the context menu for downloads.
 - New userscripts:
   * `kodi` to play videos in Kodi
   * `qr` to generate a QR code of the current URL

qutebrowser/browser/downloadview.py

@@ -140,6 +140,8 @@ class DownloadView(QListView):
             actions.append(("Remove", item.remove))
         else:
             actions.append(("Cancel", item.cancel))
+        actions.append(("Copy URL", functools.partial(
+            utils.set_clipboard, item.url().toDisplayString())))
         if model.can_clear():
             actions.append((None, None))
             actions.append(("Remove all finished", model.download_clear))