Provide constants for Markdown formatter

This commit provides constant and fields for markdown formatting
enablement

partial fix :
#4335

Author: SougandhS

org.eclipse.jdt.core/formatter/org/eclipse/jdt/core/formatter/DefaultCodeFormatterConstants.java

@@ -1510,6 +1510,19 @@ public class DefaultCodeFormatterConstants {
 	 */
 	public final static String FORMATTER_COMMENT_FORMAT_JAVADOC_COMMENT = "org.eclipse.jdt.core.formatter.comment.format_javadoc_comments"; //$NON-NLS-1$
 
+	/**
+	 * <pre>
+	 * FORMATTER / Option to control whether markdown comments are formatted
+	 *     - option id:         "org.eclipse.jdt.core.formatter.comment.format_markdown_comments"
+	 *     - possible values:   { TRUE, FALSE }
+	 *     - default:           TRUE
+	 * </pre>
+	 * @see #TRUE
+	 * @see #FALSE
+	 * @since 3.3
+	 */
+	public final static String FORMATTER_COMMENT_FORMAT_MARKDOWN_COMMENT = "org.eclipse.jdt.core.formatter.comment.format_markdown_comments"; //$NON-NLS-1$
+
 	/**
 	 * <pre>
 	 * FORMATTER / Option to control whether the header comment of a Java source file is formatted

org.eclipse.jdt.core/formatter/org/eclipse/jdt/internal/formatter/DefaultCodeFormatterOptions.java

@@ -532,6 +532,7 @@ public static DefaultCodeFormatterOptions getJavaConventionsSettings() {
 	public boolean wrap_before_assignment_operator;
 	public boolean wrap_before_switch_case_arrow_operator;
 	public boolean wrap_outer_expressions_when_nested;
+	public boolean comment_format_markdown_comment;
 
 	public int initial_indentation_level;
 	public String line_separator;
@@ -952,6 +953,7 @@ public Map<String, String> getMap() {
 		options.put(DefaultCodeFormatterConstants.FORMATTER_JOIN_LINE_COMMENTS, this.join_line_comments ? DefaultCodeFormatterConstants.TRUE : DefaultCodeFormatterConstants.FALSE);
 		options.put(DefaultCodeFormatterConstants.FORMATTER_PUT_EMPTY_STATEMENT_ON_NEW_LINE, this.put_empty_statement_on_new_line ? DefaultCodeFormatterConstants.TRUE : DefaultCodeFormatterConstants.FALSE);
 		options.put(DefaultCodeFormatterConstants.FORMATTER_LINE_SPLIT, Integer.toString(this.page_width));
+		options.put(DefaultCodeFormatterConstants.FORMATTER_COMMENT_FORMAT_MARKDOWN_COMMENT, this.comment_format_markdown_comment ? DefaultCodeFormatterConstants.TRUE : DefaultCodeFormatterConstants.FALSE);
 		switch(this.tab_char) {
 			case SPACE :
 				options.put(DefaultCodeFormatterConstants.FORMATTER_TAB_CHAR, JavaCore.SPACE);
@@ -1734,6 +1736,10 @@ else if (JavaCore.SPACE.equals(settings.get(DefaultCodeFormatterConstants.FORMAT
 		if (insertNewLineBeforeWhileInDoStatementOption != null) {
 			this.insert_new_line_before_while_in_do_statement = JavaCore.INSERT.equals(insertNewLineBeforeWhileInDoStatementOption);
 		}
+		final Object commentFormatMarkdownCommentOption = settings.get(DefaultCodeFormatterConstants.FORMATTER_COMMENT_FORMAT_MARKDOWN_COMMENT);
+		if (commentFormatMarkdownCommentOption != null) {
+			this.comment_format_markdown_comment = DefaultCodeFormatterConstants.TRUE.equals(commentFormatMarkdownCommentOption);
+		}
 
 		setString(settings, DefaultCodeFormatterConstants.FORMATTER_KEEP_ANNOTATION_DECLARATION_ON_ONE_LINE, KEEP_ON_ONE_LINE_VALUES,
 				v -> this.keep_annotation_declaration_on_one_line = v);