Add Settings for Generate Javadoc in Markdown (#4465)

Adds preference "java.codeGeneration.generateCommentsInMarkdown" to
generate javadoc in markdown style

Server side changes :
eclipse-jdtls/eclipse.jdt.ls#3837

Author: SougandhS

README.md

@@ -169,6 +169,7 @@ The following settings are supported:
 * `java.codeGeneration.hashCodeEquals.useJava7Objects`: Use Objects.hash and Objects.equals when generating the hashCode and equals methods. This setting only applies to Java 7 and higher. Defaults to `false`.
 * `java.codeGeneration.useBlocks`: Use blocks in 'if' statements when generating the methods. Defaults to `false`.
 * `java.codeGeneration.generateComments`: Generate method comments when generating the methods. Defaults to `false`.
+* `java.codeGeneration.generateCommentsInMarkdown`: Generate Javadoc comments in Markdown style when generating methods, constructors, and types. Requires source compliance >= 23. Defaults to false.
 * `java.codeGeneration.toString.template`: The template for generating the toString method. Defaults to `${object.className} [${member.name()}=${member.value}, ${otherMembers}]`.
 * `java.codeGeneration.toString.codeStyle`: The code style for generating the toString method. Defaults to `STRING_CONCATENATION`.
 * `java.codeGeneration.toString.skipNullValues`: Skip null values when generating the toString method. Defaults to `false`.

package.json

@@ -1326,6 +1326,11 @@
             "default": false,
             "scope": "window"
           },
+		  "java.codeGeneration.generateCommentsInMarkdown": {
+		    "type": "boolean",
+		    "description": "Generate Javadoc comments in Markdown style (requires source compliance >= 23).",
+		    "default": false
+		  },
           "java.codeGeneration.toString.template": {
             "type": "string",
             "description": "The template for generating the toString method.",