At the time of writing this article, Microsoft has already rolled out the modern experience to all the lists and libraries.
In the old classic sites, there was a possibility to change the the title of Wiki pages and now that is almost gone, but still there is a way to change the title.
Follow the steps below to change the wiki page title.
- In the SitePages/Pages switch to “Return to classic SharePoint” at the bottom left.
- Edit the views of “By Author” or “All Pages”.
- Add the column “Title”.
- Save the changes to the view.
- Go back to the view.
- Click on the ribbon and expand tab “Library”.
- Click on the “Quick Edit”.
- Make the changes to the respective page’s title column.
- Exit “Quick Edit” to save the changes.
Do please note that for now this works but not sure how long Microsoft will keep this option open.