gh-143089: Fix ParamSpec docstring to use list syntax instead of tuple

Type checkers (mypy and pyright) require ParamSpec defaults to use
list syntax, not tuple syntax. Updated the docstring examples to
use [int, str] instead of (int, str) to match the typing specification
and avoid misleading users.

Author: sandole

Objects/typevarobject.c

@@ -1451,13 +1451,13 @@ The following syntax creates a parameter specification that defaults\n\
 to a callable accepting two positional-only arguments of types int\n\
 and str:\n\
 \n\
-    type IntFuncDefault[**P = (int, str)] = Callable[P, int]\n\
+    type IntFuncDefault[**P = [int, str]] = Callable[P, int]\n\
 \n\
 For compatibility with Python 3.11 and earlier, ParamSpec objects\n\
 can also be created as follows::\n\
 \n\
     P = ParamSpec('P')\n\
-    DefaultP = ParamSpec('DefaultP', default=(int, str))\n\
+    DefaultP = ParamSpec('DefaultP', default=[int, str])\n\
 \n\
 Parameter specification variables exist primarily for the benefit of\n\
 static type checkers.  They are used to forward the parameter types of\n\