JavaDoc: Improvements (#2324)

This makes some improvements to JavaDoc:

- Extended support for [references](https://corochann.com/javadoc-coding-rule-of-link-linkplain-see-372.html).
- Better code support
    - Added support for `<pre>` elements
    - Added support for HTML inside code (but not `{@code}` code)
    - Fixed that the line splitting pattern required at least 2 characters per line
- Added support for HTML entities.
- Changed the line ends to `\r\n` for all test files.

components/prism-javadoc.js

@@ -1,53 +1,81 @@
 (function (Prism) {
 
-	var codeLines = {
-		'code': {
-			pattern: /(^(?:\s*(?:\*\s*)*)).*[^*\s].+$/m,
-			lookbehind: true,
-			inside: Prism.languages.java,
-			alias: 'language-java'
-		}
-	};
+	var codeLinePattern = /(^(?:\s*(?:\*\s*)*)).*[^*\s].*$/m;
+
+	var memberReference = /#\s*\w+(?:\s*\([^()]*\))?/.source;
+	var reference = /(?:[a-zA-Z]\w+\s*\.\s*)*[A-Z]\w*(?:\s*<mem>)?|<mem>/.source.replace(/<mem>/g, function () { return memberReference });
 
 	Prism.languages.javadoc = Prism.languages.extend('javadoclike', {});
 	Prism.languages.insertBefore('javadoc', 'keyword', {
-		'class-name': [
-			{
-				pattern: /(@(?:exception|throws|see|link|linkplain|value)\s+(?:[a-z\d]+\.)*)[A-Z](?:\w*[a-z]\w*)?(?:\.[A-Z](?:\w*[a-z]\w*)?)*/,
-				lookbehind: true,
-				inside: {
-					'punctuation': /\./
-				}
-			},
-			{
-				// @param <T> the first generic type parameter
-				pattern: /(@param\s+)<[A-Z]\w*>/,
-				lookbehind: true,
-				inside: {
-					'punctuation': /[.<>]/
-				}
+		'reference': {
+			pattern: RegExp(/(@(?:exception|throws|see|link|linkplain|value)\s+(?:\*\s*)?)/.source + '(?:' + reference + ')'),
+			lookbehind: true,
+			inside: {
+				'function': {
+					pattern: /(#\s*)\w+(?=\s*\()/,
+					lookbehind: true
+				},
+				'field': {
+					pattern: /(#\s*)\w+/,
+					lookbehind: true
+				},
+				'namespace': {
+					pattern: /\b(?:[a-z]\w*\s*\.\s*)+/,
+					inside: {
+						'punctuation': /\./
+					}
+				},
+				'class-name': /\b[A-Z]\w*/,
+				'keyword': Prism.languages.java.keyword,
+				'punctuation': /[#()[\],.]/
 			}
-		],
-		'namespace': {
-			pattern: /(@(?:exception|throws|see|link|linkplain)\s+)(?:[a-z\d]+\.)+/,
+		},
+		'class-name': {
+			// @param <T> the first generic type parameter
+			pattern: /(@param\s+)<[A-Z]\w*>/,
 			lookbehind: true,
 			inside: {
-				'punctuation': /\./
+				'punctuation': /[.<>]/
 			}
 		},
 		'code-section': [
 			{
-				pattern: /(\{@code\s+)(?:[^{}]|\{[^{}]*\})+?(?=\s*\})/,
+				pattern: /(\{@code\s+)(?:[^{}]|\{(?:[^{}]|\{(?:[^{}]|\{(?:[^{}]|\{[^{}]*\})*\})*\})*\})+?(?=\s*\})/,
 				lookbehind: true,
-				inside: codeLines
+				inside: {
+					'code': {
+						// there can't be any HTML inside of {@code} tags
+						pattern: codeLinePattern,
+						lookbehind: true,
+						inside: Prism.languages.java,
+						alias: 'language-java'
+					}
+				}
 			},
 			{
-				pattern: /(<(code|tt)>\s*)[\s\S]+?(?=\s*<\/\2>)/,
+				pattern: /(<(code|pre|tt)>(?!<code>)\s*)[\s\S]+?(?=\s*<\/\2>)/,
 				lookbehind: true,
-				inside: codeLines
+				inside: {
+					'line': {
+						pattern: codeLinePattern,
+						lookbehind: true,
+						inside: {
+							// highlight HTML tags and entities
+							'tag': Prism.languages.markup.tag,
+							'entity': Prism.languages.markup.entity,
+							'code': {
+								// everything else is Java code
+								pattern: /.+/,
+								inside: Prism.languages.java,
+								alias: 'language-java'
+							}
+						}
+					}
+				}
 			}
 		],
 		'tag': Prism.languages.markup.tag,
+		'entity': Prism.languages.markup.entity,
 	});
 
 	Prism.languages.javadoclike.addSupport('java', Prism.languages.javadoc);