Fix indents in Links example

Fix Links example (https://github.com/OAI/OpenAPI-Specification/blob/OpenAPI.next/versions/3.0.md#example-1):
* Fix indents
* Remove the type property from parameter, as it's already defined in the schema property
* Add a name to the link

Author: tfesenko

versions/3.0.md

@@ -2243,7 +2243,6 @@ paths:
       operationId: getRepository
       parameters: 
         - name: username
-          type: string
           in: path
           required: true
           schema:
@@ -2256,7 +2255,7 @@ paths:
       responses: 
         '200':
           description: The repository
-            content:
+          content:
               application/json: 
                 schema: 
                   $ref: '#/components/schemas/repository'
@@ -2321,7 +2320,8 @@ paths:
               schema: 
                 $ref: '#/components/schemas/pullrequest'
           links:
-            $ref: '#/components/links/PullRequestMerge'
+            pullRequestMerge:
+              $ref: '#/components/links/PullRequestMerge'
   /2.0/repositories/{username}/{slug}/pullrequests/{pid}/merge: 
     post: 
       operationId: mergePullRequest
@@ -2360,7 +2360,7 @@ components:
     RepositoryPullRequests:
       # returns '#/components/schemas/pullrequest'
       operationId: getPullRequestsByRepository
-        parameters: 
+      parameters: 
           username: $response.body#/owner/username
           slug: $response.body#/slug
     PullRequestMerge: