std.cfg: vfwscanf takes three arguments

Author: PKEuS

cfg/std.cfg

@@ -1157,7 +1157,11 @@
     <arg nr="1">
       <not-uninit/>
     </arg>
-    <arg nr="2"/>
+    <arg nr="2">
+      <not-null/>
+      <not-uninit/>
+    </arg>
+    <arg nr="3"/>
   </function>
   <!-- int fseek(FILE* stream, long int offset, int origin); -->
   <function name="fseek,std::fseek">