test: fix compatibility examples input rendering

Author: mstream

Examples.generated.md

@@ -10,7 +10,7 @@
 When there is not JSON schema differences, schema change is fully compatible.
 #### Input
 ##### JSON schema differences
-```json
+```
 no differences
 ```
 #### Output

test/unit/Test/Spec/JsonSchema/Compatibility.purs

@@ -19,7 +19,7 @@ type DiffExample = Example (Set Difference) Compatibility
 renderInput ∷ Set Difference → String
 renderInput differences =
   "##### JSON schema differences\n"
-    <> "```json\n"
+    <> "```\n"
     <> String.joinWith "\n" renderDifferences
     <> "\n```"
   where