message: Remove `target="_blank"` from "Download" button
diff: <h1>{{info.title}} <span class="api-info-version">({{info.version}})</span></h1>
  <p class="download-openapi" *ngIf="specUrl">
  Download OpenAPI specification:
  - <a class="openapi-button" [attr.download]="downloadFilename" target="_blank" [attr.href]="specUrl"> Download </a>
  + <a class="openapi-button" [attr.download]="downloadFilename" [attr.href]="specUrl"> Download </a>
  </p>
  <p>
  <!-- TODO: create separate components for contact and license ? -->
  