bpo-41819: Fix compiler warning in init_dump_ascii_wstr() (GH-22332)

Fix the compiler warning:

format specifies type `wint_t` (aka `int`) but the argument has type `unsigned int`
(cherry picked from commit c322948)

Co-authored-by: Samuel Marks <807580+SamuelMarks@users.noreply.github.com>

Python/initconfig.c

@@ -2593,7 +2593,7 @@ init_dump_ascii_wstr(const wchar_t *str)
         if (ch == L'\'') {
             PySys_WriteStderr("\\'");
         } else if (0x20 <= ch && ch < 0x7f) {
-            PySys_WriteStderr("%lc", ch);
+            PySys_WriteStderr("%c", ch);
         }
         else if (ch <= 0xff) {
             PySys_WriteStderr("\\x%02x", ch);