Fix missing tsp for codeblock in suppress warning (Azure#1355)

Found out this wasn't highlighted

docs/troubleshoot/suppresswarnings.md

@@ -16,7 +16,7 @@ Some of the rules after review can be suppressed to get clean compile outputs us
 
 For example:
 
-```
+```tsp
 #suppress "@azure-tools/typespec-providerhub/no-identifier-property-in-array-item" "Error items have no unique identifier."
 @doc("An array of details about specific errors that led to this reported error.")
 details: Error[];