Swift: Mathias's fix for the non-constant format example.

Author: geoffw0

docs/codeql/codeql-language-guides/analyzing-data-flow-in-swift.rst

@@ -140,13 +140,13 @@ The following example finds calls to ``String.init(format:_:)`` where the format
     import swift
     import codeql.swift.dataflow.DataFlow
 
-    from CallExpr call, Method method, Expr sinkExpr
+    from CallExpr call, Method method, DataFlow::Node sinkNode
     where
       call.getStaticTarget() = method and
       method.hasQualifiedName("String", "init(format:_:)") and
-      sinkExpr = call.getArgument(0).getExpr() and
+      sinkNode.asExpr() = call.getArgument(0).getExpr() and
       not exists(StringLiteralExpr sourceLiteral |
-        DataFlow::localFlow(DataFlow::exprNode(sourceLiteral), DataFlow::exprNode(sinkExpr))
+        DataFlow::localFlow(DataFlow::exprNode(sourceLiteral), sinkNode)
       )
     select call, "Format argument to " + method.getName() + " isn't hard-coded."