Add leading example sentence in C4661 and C4662 warning reference

Author: Rageking8

docs/error-messages/compiler-warnings/compiler-warning-level-1-c4661.md

@@ -15,6 +15,8 @@ A member of the template class is not defined.
 
 ## Example
 
+The following example generates C4661:
+
 ```cpp
 // C4661.cpp
 // compile with: /W1 /LD

docs/error-messages/compiler-warnings/compiler-warning-level-1-c4662.md

@@ -15,6 +15,8 @@ The specified template-class was declared, but not defined.
 
 ## Example
 
+The following example generates C4662:
+
 ```cpp
 // C4662.cpp
 // compile with: /W1 /LD