[java-jaxrs] Add Javadoc to enum (x-enum-descriptions)

Created by: jmini

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Description of the PR

Generate javadoc for enum (based on x-enum-descriptions) for JaxRS, see #1693 for more details.

Tested with:

  weather:
    type: object
    properties:
      type:
        type: integer
        format: int32
        enum:
          - 1
          - 2
          - 3
        x-enum-descriptions:
          - 'Blue sky'
          - 'Slightly overcast'
          - 'Take an umbrella with you'
        x-enum-varnames:
          - Sunny
          - Cloudy
          - Rainy

Produces:

--- a/Weather.java
+++ b/Weather.java
@@ -31,10 +31,19 @@
    * Gets or Sets type
    */
   public enum TypeEnum {
+    /**
+     * Blue sky
+     */
     Sunny(1),
     
+    /**
+     * Slightly overcast
+     */
     Cloudy(2),
     
+    /**
+     * Take an umbrella with you
+     */
     Rainy(3);
 
     private Integer value;