bpo-40268: Remove a few pycore_pystate.h includes (GH-19510)

diff --git a/Modules/_io/textio.c b/Modules/_io/textio.c
index 95b023d..9e33c1e 100644
--- a/Modules/_io/textio.c
+++ b/Modules/_io/textio.c
@@ -8,8 +8,9 @@
 
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
+#include "pycore_interp.h"      // PyInterpreterState.fs_codec
 #include "pycore_object.h"
-#include "pycore_pystate.h"
+#include "pycore_pystate.h"     // _PyInterpreterState_GET()
 #include "structmember.h"
 #include "_iomodule.h"