Corrected capitalization, corrected to American spellings and typos (#30685)

* Translate challenge subtitles and example challenge text to Spanish

* Corrected errors in syntax and punctuation

* Multiple corrections of it/s to its plus other grammar corrections

* Correction and added paragraph to CSS Flex article

* Corrected my own typo

* Corrected capitalization, American spellings and typos

guide/english/containers/docker/index.md

@@ -5,7 +5,7 @@ title: Docker
 
 [Docker](https://www.docker.com/) is a widely-used container platform available for Linux, Windows, and Mac, as well as cloud providers like AWS and Azure.
 
-A common use case would be to package an app and all it's requirements in a container. The container can then be used during development, passed to quality assurance/testing, and on to production/operations. This eliminates the "works on my machine" mentality, as the container effectively _is_ the machine, no matter what actual hardware it may be running on.
+A common use case would be to package an app and all its requirements in a container. The container can then be used during development, passed to quality assurance/testing, and on to production/operations. This eliminates the "works on my machine" mentality, as the container effectively _is_ the machine, no matter what actual hardware it may be running on.
 
 After you are done setting up your computer and installig docker, you can simply test your Docker by running command:
 

guide/english/containers/docker/useful-commands-for-docker/index.md

@@ -120,7 +120,7 @@ Docker by default takes space from **/** drive of host system to store data. Ove
 Let the partition created is **mypart**
 - Then, run following command
 `$ docker run –it -v /mypart:/data centos`
-  - **mypart** is a partition in base system and **data** is the folder where docker will store it's data.
+  - **mypart** is a partition in base system and **data** is the folder where docker will store its data.
   - **v** - volume
 
 ### Attaching dvd to a container