fix: change application json for inline command format

drumath2237 · web-flow · commit 32aa90ffe182 · 2022-02-15T20:35:44.000+09:00
diff --git a/articles/azure-signalr/concept-upstream.md b/articles/azure-signalr/concept-upstream.md
@@ -150,7 +150,7 @@ POST
 
 #### Connected
 
-Content-Type: application/json
+Content-Type: `application/json`
 
 #### Disconnected
 
