Docs: Extending terminology & improving  hyper-link

This PR is based on commit e12e2b89. It extends the changes across
all available Docker docs sources to date.

It also corrects hyper-links and their labels where necessary.

Docker-DCO-1.1-Signed-off-by: O.S. Tezer <ostezer@gmail.com> (github: ostezer)
Merge pull request #3 from ostezer/privreg

Docs: Extending terminology & improving  hyper-link