Issue #28585: Restored docstring of os._isdir().

diff --cc Modules/clinic/posixmodule.c.h
index 9de5b0391f79e8750ee1644066c472cc6c77c7bb,f63a3beabf9ef735ad19e310236117a9a8212748..2c0074a1a569fbb5d8a3b810aaeee0c4c6c32b4d
--- 1/Modules/clinic/posixmodule.c.h
--- 2/Modules/clinic/posixmodule.c.h
+++ b/Modules/clinic/posixmodule.c.h
@@@ -6351,4 -6149,4 +6352,4 @@@ exit
  #ifndef OS_GETRANDOM_METHODDEF
      #define OS_GETRANDOM_METHODDEF
  #endif /* !defined(OS_GETRANDOM_METHODDEF) */
- /*[clinic end generated code: output=e4a3bd36c7bb8356 input=a9049054013a1b77]*/
 -/*[clinic end generated code: output=50cfb7ebc44efb67 input=a9049054013a1b77]*/
++/*[clinic end generated code: output=61abf6df195aa5f1 input=a9049054013a1b77]*/

diff --cc Modules/posixmodule.c
Simple merge