Display the list of completions, COMPLETIONS, using `standard-output'.
Each element may be just a symbol or string
or may be a list of two strings to be printed as if concatenated.
If it is a list of two strings, the first is the actual completion
alternative, the second serves as annotation.
`standard-output' must be a buffer.
The actual completion alternatives, as inserted, are given `mouse-face'
properties of `highlight'.
At the end, this runs the normal hook `completion-setup-hook'.
It can find the completion buffer in `standard-output'.
The obsolete optional arg COMMON-SUBSTRING, if non-nil, should be a string
specifying a common substring for adding the faces
`completions-first-difference' and `completions-common-part' to
the completions buffer. (fn COMPLETIONS &optional COMMON-SUBSTRING)