Finish conversion of the struct module to Argument Clinic

[serhiy-storchaka]

Feature or enhancement

The struct module was partially converted to Argument Clinic years ago, but some functions take variable number of arguments, and Argument Clinic did not support this at that time. Also, While Struct.__init__ was converted to Argument clinic, the signature was not exposed for the Struct constructor.

Linked PRs

• gh-143672: Finish conversion of the struct module to Argument Clinic #143857

[skirpichev]

@serhiy-storchaka, beware on #143672 ;-)

[serhiy-storchaka]

Oh sorry, I searched for open issues but did not see that one.