bpo-44791: Fix substitution of ParamSpec in Concatenate with different parameter expressions (GH-27518)


* Substitution with a list of types returns now a tuple of types.
* Substitution with Concatenate returns now a Concatenate with
  concatenated lists of arguments.
* Substitution with Ellipsis is not supported.
(cherry picked from commit ecfacc362dd7fef7715dcd94f2e2ca6c622ef115)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
4 files changed