Filter: Consider presence of +PENDING tag signal to skip completed.data

This puts +PENDING at the same level of treatment as status:pending when
it comes to decision whether the data processed should be pending only.

The mechanism is by no means perfect and should be improved in the
future.

src/Filter.cpp

@@ -214,6 +214,7 @@ bool Filter::pendingOnly () const
   int countOr        = 0;
   int countXor       = 0;
   int countNot       = 0;
+  bool pendingTag = false;
 
   for (const auto& a : Context::getContext ().cli2._args)
   {
@@ -232,12 +233,21 @@ bool Filter::pendingOnly () const
     }
   }
 
+  for (const auto& word : Context::getContext ().cli2._original_args)
+  {
+    if (word.attribute ("raw") == "+PENDING")  pendingTag = true;
+  }
+
+
   if (countUUID)
     return false;
 
   if (countOr || countXor || countNot)
     return false;
 
+  if (pendingTag)
+    return true;
+
   if (countStatus)
   {
     if (!countPending && !countWaiting && !countRecurring)