[rust][client] fix enum type usage

[qavvvzdhwm]

PR checklist

• Read the contribution guidelines.
• If contributing template-only or documentation-only changes which will change sample output, build the project before.
• Run the shell script(s) under ./bin/ (or Windows batch scripts under.\bin\windows) to update Petstore samples related to your fix. This is important, as CI jobs will verify all generator outputs of your HEAD commit, and these must match the expectations made by your contribution. You only need to run ./bin/{LANG}-petstore.sh, ./bin/openapi3/{LANG}-petstore.sh if updating the code or mustache templates for a language ({LANG}) (e.g. php, ruby, python, etc).
• File the PR against the correct branch: master, 4.3.x, 5.0.x. Default: master.
• Copy the technical committee to review the pull request if your PR is targeting a particular programming language.

PR description

The model template was referring to the enum name in the context instead of the enum-updated type.

openapi: 3.0.0
info:
  title: rust array of enums bug
  version: 1.0.0
paths:
  /:
    get:
      operationId: Op1
      tags:
        - array-enum
      responses:
        "200":
          description: ""
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/ResponseFizzesBuzzes"
      requestBody:
        content:
          application/json:
            schema:
              type: integer
components:
  schemas:
    ResponseFizzesBuzzes:
      type: object
      properties:
        fizzes_buzzes:
          type: array
          items:
            type: string
            enum:
              - fizz
              - buzz
              - fizz_buzz
      required:
        - fizzes_buzzes

generated originally:

    pub fizzes_buzzes: FizzesBuzzes,

fixed:

    pub fizzes_buzzes: Vec<FizzesBuzzes>,

cc: @frol, @farcaller, @bjgill, @richardwhiuk

[auto-labeler]

👍 Thanks for opening this issue!
🏷 I have applied any labels matching special text in your issue.

The team will review the labels and make any necessary changes.