Add Prettier plugin for Nunjuck templates (#3887)

prettier.config.mjs

@@ -1,10 +1,17 @@
 const config = {
+	plugins: ["prettier-plugin-jinja-template"],
 	overrides: [
 		{
 			files: "*.md",
 			options: {
 				parser: "markdown"
 			}
+		},
+		{
+			files: ["*.njk"],
+			options: {
+				parser: "jinja-template"
+			}
 		}
 	],
 	trailingComma: "none"