docs: add syntax highlighting for ndjson

`json` seems to work for me.

Author: lishaduck

documentation/tooling-integration.md

@@ -132,7 +132,7 @@ Alternatively, you can use `--report=ndjson` to print each review error on its o
 
 This can be useful to send `elm-review` errors to logging/monitoring services.
 
-```
+```json
 {"path":"src/Main.elm","rule":"NoUnused.Variables","message":"Imported variable `span` is not used","ruleLink":"https://package.elm-lang.org/packages/jfmengels/review-unused/2.1.3/NoUnused-Variables","details":["You should either use this value somewhere, or remove it at the location I pointed at."],"region":{"start":{"line":10,"column":11},"end":{"line":10,"column":15}},"fix":[{"range":{"start":{"line":8,"column":14},"end":{"line":10,"column":15}},"string":""}],"formatted":[{"string":"(fix) ","color":"#33BBC8"},{"string":"NoUnused.Variables","color":"#FF0000","href":"https://package.elm-lang.org/packages/jfmengels/review-unused/2.1.3/NoUnused-Variables"},": Imported variable `span` is not used\n\n 9|           -- span is unused\n10|         , span\n             ",{"string":"^^^^","color":"#FF0000"},"\n11|         , text\n\nYou should either use this value somewhere, or remove it at the location I pointed at."]}
 {"path":"src/Main.elm","rule":"NoUnused.CustomTypeConstructors","message":"Type constructor `UnusedCustomType` is not used.","ruleLink":"https://package.elm-lang.org/packages/jfmengels/review-unused/2.1.3/NoUnused-CustomTypeConstructors","details":["This type constructor is never used. It might be handled everywhere it might appear, but there is no location where this value actually gets created."],"region":{"start":{"line":28,"column":7},"end":{"line":28,"column":23}},"formatted":["",{"string":"NoUnused.CustomTypeConstructors","color":"#FF0000","href":"https://package.elm-lang.org/packages/jfmengels/review-unused/2.1.3/NoUnused-CustomTypeConstructors"},": Type constructor `UnusedCustomType` is not used.\n\n27|     | Decrement\n28|     | UnusedCustomType\n          ",{"string":"^^^^^^^^^^^^^^^^","color":"#FF0000"},"\n\nThis type constructor is never used. It might be handled everywhere it might appear, but there is no location where this value actually gets created."]}
 ```