Update docs/error-messages/compiler-errors-2/compiler-error-c3909.md

Co-authored-by: Copilot <[email protected]>

Author: TylerMSFT

docs/error-messages/compiler-errors-2/compiler-error-c3909.md

@@ -7,7 +7,7 @@ helpviewer_keywords: ["C3909"]
 ---
 # Compiler Error C3909
 
-> aWinRT or managed event declaration must occur in a WinRT or managed type
+> a WinRT or managed event declaration must occur in a WinRT or managed type
 
 ## Remarks