doc: printf: detail exactly which escapes are supported

doc: printf: detail exactly which escapes are supported

* doc/coreutils.texi (echo invocation): Parameterize the escape list.
(printf invocation): Remove the C escape reference as it mentions
\' which we don't support, and doesn't mention \e which we do support
(and GCC also does).  Instead directly present the escape list
as done for the echo command, adjusted accordingly.