improve incorrect French (#23109)

Following suggestions from Clément.

Doc/howto/unicode.rst

@@ -32,8 +32,8 @@ For a while people just wrote programs that didn't display accents.  I remember
 looking at Apple ][ BASIC programs, published in French-language publications in
 the mid-1980s, that had lines like these::
 
-   PRINT "FICHIER EST COMPLETE."
-   PRINT "CARACTERE NON ACCEPTE."
+   PRINT "MISE A JOUR TERMINEE"
+   PRINT "PARAMETRES ENREGISTRES"
 
 Those messages should contain accents, and they just look wrong to someone who
 can read French.