Fix stray url from beta-docs warning (remove aws bucket URI)

Docker-DCO-1.1-Signed-off-by: O.S. Tezer <ostezer@gmail.com> (github: ostezer)

(cherry picked from commit 5e5230cb190b6d78cf27706da447d179b79b29b6)

Docker-DCO-1.1-Signed-off-by: O.S.Tezer <ostezer@gmail.com> (github: SvenDowideit)
 - unix://path/to/socket should read unix:///path/to/socket like the rest of the documentation (a slash was missing)
 - Mention that [] options may be specified multiple times on the Usage page

Docker-DCO-1.1-Signed-off-by: Mike MacCana <mike.maccana@gmail.com> (github: mikemaccana)

Docker-DCO-1.1-Signed-off-by: Mike MacCana <mike.maccana@gmail.com> (github: SvenDowideit)

(cherry picked from commit e62efb266fd878453b8562e60b06a3e579fe571a)
add a reference to multiple -H options, and update the other example of -H option

and copy changes to the cli.md file

Docker-DCO-1.1-Signed-off-by: Sven Dowideit <SvenDowideit@fosiki.com> (github: SvenDowideit)

(cherry picked from commit b2c87fe08b71523eb20fed63e5da3bef30b756ec)
Docs: Add docs new version files created by `make docs` to .gitignore

Files are:

 - docs/AWS_S3_BUCKET
 - docs/GIT_BRANCH
 - docs/VERSION

Docker-DCO-1.1-Signed-off-by: O.S. Tezer <ostezer@gmail.com> (github: ostezer)

Update:

 - Remove unnecessary last blankline

(cherry picked from commit d9f9021e9b8bc46481b4c2bb28786fd3f0b88b9c)

Docker-DCO-1.1-Signed-off-by: O.S.Tezer <ostezer@gmail.com> (github: SvenDowideit)