Overhaul existing example in C2601 error reference

Author: Rageking8

docs/error-messages/compiler-errors-2/compiler-error-c2601.md

@@ -18,15 +18,22 @@ Or, there may be an extra/missing brace before the location of the C2601 error.
 
 ## Examples
 
-The following sample generates C2601:
+## Define function within a function
 
-```cpp
-// C2601.cpp
-int main() {
-   int i = 0;
+[Lambda Expressions](../../cpp/lambda-expressions-in-cpp.md) may be used to emulate the behavior of local functions:
 
-   void funcname(int j) {   // C2601
-      j++;
-   }
+```cpp
+// C2601a.cpp
+int main()
+{
+    int increment(int value)   // C2601
+    {
+        return value + 1;
+    }
+
+    // Try the following line instead:
+    // auto increment = [](int value) { return value + 1; };
+
+    int two = increment(1);
 }
 ```