dolphin.zsh: complete both directories and URL protocols

Dolphin is mostly used for navigating local paths (or remote paths
mounted locally), so it is important to have directories completed as
well as URLs

completions/dolphin.zsh

@@ -6,13 +6,19 @@
 
 local ret=1
 
+# complete both URL protocols and local directories
+_urls_and_dirs() {
+  _urls
+  _directories
+}
+
 _arguments -C \
   '(* -)'{-h,--help}'[Displays help on commandline options]' \
   '--select[The files and folders passed as arguments will be selected.]' \
   '--split[Dolphin will get started with a split view.]' \
   '--new-window[Dolphin will explicitly open in a new window.]' \
   '--daemon[Start Dolphin Daemon (only required for DBus Interface).]' \
-  '*:: :_urls' \
+  '*:: :_urls_and_dirs' \
   && ret=0
 
 return $ret