std.cfg: Added support for std::string:swap().

cfg/std.cfg

@@ -5914,6 +5914,13 @@ The obsolete function 'gets' is called. With 'gets' you'll get a buffer overrun
     <returnValue type="char"/>
     <use-retval/>
   </function>
+  <!-- void swap (string& str); -->
+  <function name="std::string::swap">
+    <noreturn>false</noreturn>
+    <arg nr="1">
+      <not-uninit/>
+    </arg>
+  </function>
   <function name="std::string::c_str,std::string::data">
     <noreturn>false</noreturn>
     <returnValue type="const char *"/>