- Add link to valid image name and tag formats in referenced files
- Per review comments, updated docs to remove reference to `USERNAME` and
`REGISTRYHOST`.
- Per review comment, removed links from man page.
- Per review comment, added and updated examples on `docker tag`
Signed-off-by: Subhajit Ghosh <isubuz.g@gmail.com>
Upstream-commit: 2f4d9eb6b1
Component: cli