Polish "Specify language derived from Content-Type in body snippets"

See gh-797

spring-restdocs-core/src/main/java/org/springframework/restdocs/payload/AbstractBodySnippet.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2019 the original author or authors.
+ * Copyright 2014-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -31,6 +31,7 @@ import org.springframework.restdocs.snippet.TemplatedSnippet;
  * document a RESTful resource's request or response body.
  *
  * @author Andy Wilkinson
+ * @author Achim Grimm
  */
 public abstract class AbstractBodySnippet extends TemplatedSnippet {
 
@@ -73,11 +74,7 @@ public abstract class AbstractBodySnippet extends TemplatedSnippet {
 	protected Map<String, Object> createModel(Operation operation) {
 		try {
 			MediaType contentType = getContentType(operation);
-			String language = null;
-			if (contentType != null) {
-				language = (contentType.getSubtypeSuffix() != null) ? contentType.getSubtypeSuffix()
-						: contentType.getSubtype();
-			}
+			String language = determineLanguage(contentType);
 			byte[] content = getContent(operation);
 			if (this.subsectionExtractor != null) {
 				content = this.subsectionExtractor.extractSubsection(content, contentType);
@@ -94,6 +91,13 @@ public abstract class AbstractBodySnippet extends TemplatedSnippet {
 		}
 	}
 
+	private String determineLanguage(MediaType contentType) {
+		if (contentType == null) {
+			return null;
+		}
+		return (contentType.getSubtypeSuffix() != null) ? contentType.getSubtypeSuffix() : contentType.getSubtype();
+	}
+
 	private Charset extractCharset(MediaType contentType) {
 		if (contentType == null) {
 			return null;

spring-restdocs-core/src/main/resources/org/springframework/restdocs/templates/asciidoctor/default-request-part-body.snippet

@@ -1,4 +1,4 @@
-[source,options="nowrap"]
+[source{{#language}},{{language}}{{/language}},options="nowrap"]
 ----
 {{body}}
 ----

spring-restdocs-core/src/main/resources/org/springframework/restdocs/templates/markdown/default-request-part-body.snippet

@@ -1,3 +1,3 @@
-```
+```{{#language}}{{language}}{{/language}}
 {{body}}
 ```