These were deprecated in 6c400a9c2009bba9376ad61ab59c04c1ad675871 (docker 19.03),
but the "Deprecated:" comments were missing a newline before them.
While most IDEs will detect such comments as "deprecated", pkg.go.dev and linters
will ignore them, which may result in users not being aware of them being deprecated.
This patch;
- Fixes the "Deprecated:" comments.
- Changes the var aliases to functions, which is slightly more boilerplating,
but makes sure the functions are documented as "function", instead of shown
in the "variables" section on pkg.go.dev.
- Adds some punctuation and adds "doc links", which allows readers to navigate
to related content on pkg.go.dev.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>