Fix punctuation and formatting in README.md

Corrected punctuation and formatting in README.

Author: JerryI

container/README.md

@@ -10,7 +10,7 @@ A docker container for the [Wolfram JS Frontend](https://github.com/JerryI/wolfr
 
 2. Register at the [Wolfram Engine download page](https://www.wolfram.com/engine/). Click to download (only needed to be redirected to the right place) and then follow the `Get your license` instructions. Register on the next page and acquire the license (it is free). A confirmation message will be sent to your email address. Please follow the link received by email.
 
-3. Start the container (*not by a superuser*):
+3. Start the container (*not by a superuser!*):
     For example
 
     ```bash
@@ -40,7 +40,7 @@ A docker container for the [Wolfram JS Frontend](https://github.com/JerryI/wolfr
 
 You may change port mapping in the starting sequence.
 
-## How to update an image
+## How to update
 To feath a new version, you need to purge the old one including a named volume
 
 ```bash
@@ -95,6 +95,7 @@ docker run -it \
 To update WLJS Notebook image, please, remove named volume `wljs_data` as well. Otherwise some packages may appear to be outdated
 
 ## Running as root
+*Not recommended*
 Change the mounting directories
 
 ```bash