Simplify language, consider style guide

[dtrudg]

Which Document page:

Various, but especially

• https://sylabs.io/guides/3.4/user-guide/singularity_and_docker.html

Expected results:

Concepts are expressed as simply as possible.

Actual results:

There is a lot of use of the passive voice, and long sentences. Makes it difficult to skim the documents quickly.

Consider rewriting some sections in simpler English where possible. Consider guides e.g.

http://www.plainenglish.co.uk/files/howto.pdf
http://www.plainenglish.co.uk/files/alternative.pdf