bpo-30600: Fix error messages (condition order in Argument Clinic) (#2051)

The function '_PyArg_ParseStack()' and
'_PyArg_UnpackStack' were failing (with error
"XXX() takes Y argument (Z given)") before
the function '_PyArg_NoStackKeywords()' was called.
Thus, the latter did not raise its more meaningful
error : "XXX() takes no keyword arguments".
diff --git a/Objects/clinic/floatobject.c.h b/Objects/clinic/floatobject.c.h
index d9ac39d..893629b 100644
--- a/Objects/clinic/floatobject.c.h
+++ b/Objects/clinic/floatobject.c.h
@@ -58,13 +58,13 @@
     PyObject *return_value = NULL;
     PyObject *o_ndigits = NULL;
 
-    if (!_PyArg_UnpackStack(args, nargs, "__round__",
-        0, 1,
-        &o_ndigits)) {
+    if (!_PyArg_NoStackKeywords("__round__", kwnames)) {
         goto exit;
     }
 
-    if (!_PyArg_NoStackKeywords("__round__", kwnames)) {
+    if (!_PyArg_UnpackStack(args, nargs, "__round__",
+        0, 1,
+        &o_ndigits)) {
         goto exit;
     }
     return_value = float___round___impl(self, o_ndigits);
@@ -273,12 +273,12 @@
     const char *typestr;
     const char *fmt;
 
-    if (!_PyArg_ParseStack(args, nargs, "ss:__set_format__",
-        &typestr, &fmt)) {
+    if (!_PyArg_NoStackKeywords("__set_format__", kwnames)) {
         goto exit;
     }
 
-    if (!_PyArg_NoStackKeywords("__set_format__", kwnames)) {
+    if (!_PyArg_ParseStack(args, nargs, "ss:__set_format__",
+        &typestr, &fmt)) {
         goto exit;
     }
     return_value = float___set_format___impl(type, typestr, fmt);
@@ -313,4 +313,4 @@
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=dc6b0b67a7e40c93 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=b2271e7413b36162 input=a9049054013a1b77]*/