(Core) - fiing listingEntry

Fixing listingEntry

include/management/class_ListingEntry.inc

@@ -57,24 +57,24 @@ class ListingEntry implements ArrayAccess
     $this->row      = $row;
   }
 
-  public function offsetSet ($offset, $value)
+  public function offsetSet ($offset, $value) : void
   {
     $this->attrs[$offset] = $value;
   }
 
-  public function offsetExists ($offset)
+  public function offsetExists ($offset) : bool
   {
     return isset($this->attrs[$offset]);
   }
 
-  public function offsetUnset ($offset)
+  public function offsetUnset ($offset) : void
   {
     unset($this->attrs[$offset]);
   }
 
-  public function offsetGet ($offset)
+  public function offsetGet ($offset) : mixed
   {
-    return (isset($this->attrs[$offset]) ? $this->attrs[$offset] : NULL);
+    return ($this->attrs[$offset] ?? NULL);
   }
 
   public function getPid (): string