message: fix(docs-infra): remove redundant main roles
  remove redundant main role as pages should always have a
  single element with a main role (also remove the role assigne
  to the main tag as that is implied)
  PR Close
diff: <aio-search-results #searchResultsView *ngIf="showSearchResults" [searchResults]="searchResults | async" (resultSelected)="hideSearchResults()"></aio-search-results>
  -<mat-sidenav-container class="sidenav-container" [class.no-animations]="disableAnimations" [class.has-floating-toc]="hasFloatingToc" role="main">
  +<mat-sidenav-container class="sidenav-container" [class.no-animations]="disableAnimations" [class.has-floating-toc]="hasFloatingToc">
  <mat-sidenav [ngClass]="{'collapsed': !dockSideNav}" #sidenav class="sidenav" [mode]="mode" [opened]="isOpened" (openedChange)="updateHostClasses()">
  <aio-nav-menu *ngIf="!showTopMenu" [nodes]="topMenuNarrowNodes" [currentNode]="currentNodes?.TopBarNarrow" [isWide]="dockSideNav"></aio-nav-menu>
  <section class="sidenav-content-container">
  - <main class="sidenav-content" [id]="pageId" role="main">
  + <main class="sidenav-content" [id]="pageId">
  <div id="main-content" tabindex="-1"></div>
  <aio-mode-banner [mode]="deployment.mode" [version]="versionInfo"></aio-mode-banner>
  <aio-doc-viewer [class.no-animations]="disableAnimations" [doc]="currentDocument" (docReady)="onDocReady()" (docRemoved)="onDocRemoved()" (docInserted)="onDocInserted()" (docRendered)="onDocRendered()">
  