bpo-35133: Fix mistakes when concatenate string literals on different lines. (GH-10284)


Two kind of mistakes:

1. Missed space. After concatenating there is no space between words.

2. Missed comma. Causes unintentional concatenating in a list of strings.
(cherry picked from commit 34fd4c20198dea6ab2fe8dc6d32d744d9bde868d)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
diff --git a/Modules/_io/textio.c b/Modules/_io/textio.c
index 73d1b2e..9d0d9ca 100644
--- a/Modules/_io/textio.c
+++ b/Modules/_io/textio.c
@@ -1313,7 +1313,7 @@
     /* Check if something is in the read buffer */
     if (self->decoded_chars != NULL) {
         if (encoding != Py_None || errors != Py_None || newline_obj != NULL) {
-            _unsupported("It is not possible to set the encoding or newline"
+            _unsupported("It is not possible to set the encoding or newline "
                          "of stream after the first read");
             return NULL;
         }