MAPG-78 [fix] add missing return types to some methods

src/Interfaces/Database/IResultSet.php

@@ -8,9 +8,9 @@ interface IResultSet
 
     const FETCH_BOTH = 2;
 
-    public function fetch(int $type);
+    public function fetch(int $type): ?array;
 
-    public function fetchAll(int $type);
+    public function fetchAll(int $type): array;
 
-    public function fetchOneColumn(string $valueName, string $keyName);
+    public function fetchOneColumn(string $valueName, string $keyName): array;
 }