feat: x-enum-description support added to kotlin-server code generator

[deicon]

Using the x-enum-description it's possible to add descriptive comments onto the generated enum values.
This PR adds the comments per enum value based on this extension to kotlin-server generator.

Kotlin committee members

@jimschubert
@dr4ke616
@karismann @Zomzog @andrewemery @4brunu @yutaka0m @stefankoppier

components:
  schemas:
    Pony:
      type: object
      properties:
        type:
          $ref: '#/components/schemas/Type'
    Type:
      type: string
      enum:
        - Earth
        - Pegasi
        - Mercury
      x-enum-descriptions:
        - The planet we all live on
        - Pegasi b is a gas giant exoplanet that orbits a G-type star
        - Mercury is the first planet from the Sun and the smallest in the Solar System

will generate a comment on each value

...
/**
 * 
 *
 * Values: Earth,Pegasi,Mercury
 */


enum class Type(val value: kotlin.String) {


    /**
    * The planet we all live on
    */
    @JsonProperty(value = "Earth")
    Earth("Earth"),


    /**
    * Pegasi b is a gas giant exoplanet that orbits a G-type star
    */
    @JsonProperty(value = "Pegasi")
    Pegasi("Pegasi"),
...

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