patch 8.2.0074: Python 3 unicode test someitmes fails

Problem:    Python 3 unicode test someitmes fails.
Solution:   Make 'termencoding' empty.  Correct number of error message.

runtime/doc/message.txt

@@ -76,7 +76,7 @@ See `:messages` above.
 LIST OF MESSAGES
 			*E222* *E228* *E232* *E256* *E293* *E298* *E304* *E317*
 			*E318* *E356* *E438* *E439* *E440* *E316* *E320* *E322*
-			*E323* *E341* *E473* *E570* *E685* *E950*  >
+			*E323* *E341* *E473* *E570* *E685* *E292*  >
   Add to read buffer
   makemap: Illegal mode
   Cannot create BalloonEval with both message and callback

runtime/doc/options.txt

@@ -7694,7 +7694,7 @@ A jump table for the options with a short description can be found at |Q_op|.
 	the GUI it only applies to the keyboard ('encoding' is used for the
 	display).  Except for the Mac when 'macatsui' is off, then
 	'termencoding' should be "macroman".
-								*E617*
+								*E617* *E950*
 	Note: This does not apply to the GTK+ GUI.  After the GUI has been
 	successfully initialized, 'termencoding' is forcibly set to "utf-8".
 	Any attempts to set a different value will be rejected, and an error

src/change.c

@@ -1218,7 +1218,7 @@ del_bytes(
     // If "count" is negative the caller must be doing something wrong.
     if (count < 1)
     {
-	siemsg("E950: Invalid count for del_bytes(): %ld", count);
+	siemsg("E292: Invalid count for del_bytes(): %ld", count);
 	return FAIL;
     }
 

src/testdir/test_python3.vim

@@ -170,11 +170,18 @@ endfunc
 
 func Test_unicode()
   " this crashed Vim once
+  let save_tenc = &tenc
+  set tenc=
+
   set encoding=utf32
   py3 print('hello')
+
   set encoding=debug
   py3 print('hello')
+
   set encoding=euc-tw
   py3 print('hello')
+
   set encoding=utf8
+  let &tenc = save_tenc
 endfunc

src/version.c

@@ -742,6 +742,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    74,
 /**/
     73,
 /**/