Make some attempt to respect "Clear Private Data"

vimperator/content/config.js

@@ -302,7 +302,8 @@ const config = { //{{{
             },
             {
                 completer: function (context) completion.url(context),
-                literal: 0
+                literal: 0,
+                privateData: true
             });
 
         /////////////////////////////////////////////////////////////////////////////}}}

vimperator/locale/en-US/autocommands.txt

@@ -33,6 +33,7 @@ Available {events}:
 |*PageLoadPre*       |Triggered after a page load is initiated
 |*PageLoad*          |Triggered when a page gets (re)loaded/opened
 |*PrivateMode*	     |Triggered when private mode is activated or deactivated
+|*Sanitize*	     |Triggered when privata data are sanitized
 |*ShellCmdPost*      |Triggered after executing a shell command with [c]:![c]{cmd}
 |*VimperatorEnter*   |Triggered after Firefox starts
 |*VimperatorLeavePre*|Triggered before exiting Firefox, just before destroying each module