fix: update apt source filename in ubuntu uninstall

Signed-off-by: David Karlsson <[email protected]>

Author: dvdksn

content/manuals/engine/install/ubuntu.md

@@ -301,7 +301,7 @@ To upgrade Docker Engine, download the newer package files and repeat the
 3. Remove source list and keyrings
 
    ```console
-   $ sudo rm /etc/apt/sources.list.d/docker.list
+   $ sudo rm /etc/apt/sources.list.d/docker.sources
    $ sudo rm /etc/apt/keyrings/docker.asc
    ```