Add docs for sidebar.shares.showAllOnLoad configuration option

docs/getting-started.md

@@ -55,6 +55,7 @@ substring of a value of the authenticated user. Examples are `/Shares`, `/{{.Id}
   - `options.feedbackLink.ariaLabel` Since the link only has an icon, you can set an e.g. screen reader accessible label. Defaults to `ownCloud feedback survey`.
   - `options.feedbackLink.description` Provide any description you want to see as tooltip and as accessible description. Defaults to `Provide your feedback: We'd like to improve the web design and would be happy to hear your feedback. Thank you! Your ownCloud team.` 
 - `options.sharingRecipientsPerPage` Sets the amount of users shown as recipients in the dropdown when sharing resources. Default amount is 200.
+- `options.sidebar.shares.showAllOnLoad` Sets the list of (link) shares list in the sidebar to be initially expanded (default is a collapsed state, only showing the first three shares).
 
 ## Setting up backend and running