Add blockquotes for C2018 error message

Rageking8 · web-flow · commit 929d024a7b7f · 2025-06-21T18:10:33.000+08:00
diff --git a/docs/error-messages/compiler-errors-1/compiler-error-c2018.md b/docs/error-messages/compiler-errors-1/compiler-error-c2018.md
@@ -8,7 +8,7 @@ ms.assetid: 86b54573-dca0-4446-be1a-e3ac489c073b
 ---
 # Compiler Error C2018
 
-unknown character 'hexnumber'
+> unknown character 'hexnumber'
 
 The source file contains an unexpected ASCII character, which is identified by its hex number. To resolve the error, remove the character.
 
