qt.cfg: Add configuration for function QString::chopped()

Reference: https://doc.qt.io/qt-5/qstring.html#chopped

cfg/qt.cfg

@@ -919,6 +919,18 @@
       <not-bool/>
     </arg>
   </function>
+  <!-- QString QString::chopped(int len) const -->
+  <function name="QString::chopped">
+    <noreturn>false</noreturn>
+    <returnValue type="QString"/>
+    <use-retval/>
+    <const/>
+    <arg nr="1" direction="in">
+      <not-uninit/>
+      <not-bool/>
+      <valid>0:</valid>
+    </arg>
+  </function>
   <!-- void QString::clear() -->
   <function name="QList::clear,QString::clear">
     <noreturn>false</noreturn>