fix: Replace "syntax" with "xml" code fences

Used find/replace regex in VS Code
Find:``` syntax(\s\n*)<\?xml
Replace:```xml$1<?xml

windows/client-management/mdm/policy-csp-exploitguard.md

@@ -82,7 +82,7 @@ ADMX Info:
 <!--Example-->
 Here is an example:
 
-``` syntax
+```xml
 <?xml version="1.0" encoding="utf-8"?>
 <SyncML xmlns="SYNCML:SYNCML1.1">
   <SyncBody>