Take out http (#1084)

Author: jooyoungseo

snippets/rmarkdown.json

@@ -110,7 +110,7 @@
 	},
 	"Insert image": {
 		"prefix": "image",
-		"body": "![${1:alt}](http://${2:link})$0",
+		"body": "![${1:alt}](${2:link})$0",
 		"description": "Insert image"
 	},
 	"Insert code chunk": {