[RN] Fix documentation comments

* Javadoc introduced @code as a replacement of <code> and <tt> which is
  better aligned with other javadoc tags such as @link. Use it in the
  Java source code. If we switch to Kotlin, then we'll definitely use
  Markdown.

* There are more uses of @code in the JavaScript source code than <tt>
  so use @code for the sake of consistency. Eventually, I'd rather we
  switch to Markdown because it's easier on my eyes.

* Xcode is plain confused by @code and @link. The Internet says that
  Xcode supports the backquote character to denote the beginning and end
  of a string of characters which should be formatted for display as
  code but it doesn't work for me. <tt> is not rendered at all. So use
  the backquote which is rendered itself. Hopefully, if we switch to
  Markdown, then it'll be common between JavaScript and Objective-C
  source code.

react/features/authentication/components/WaitForOwnerDialog.native.js

@@ -100,9 +100,9 @@ class WaitForOwnerDialog extends Component {
     }
 
     /**
-     * Renders a specific <tt>string</tt> which may contain HTML.
+     * Renders a specific {@code string} which may contain HTML.
      *
-     * @param {string} html - The <tt>string</tt> which may contain HTML to
+     * @param {string} html - The {@code string} which may contain HTML to
      * render.
      * @returns {ReactElement[]|string}
      */