Update docs/error-messages/compiler-warnings/compiler-warning-level-1-c4042.md

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: TylerMSFT

docs/error-messages/compiler-warnings/compiler-warning-level-1-c4042.md

@@ -23,7 +23,7 @@ This warning can be caused by specifying a storage class other than **`register`
 
 ## Example
 
-The following example generates C4042
+The following example generates C4042:
 
 ```cpp
 // C4042.cpp