xep-0308: Make /correct work without quotation marks

Now we can specify an unlimited amount of arguments for commands.
Maybe this is also helpful for other commands that use quotation marks
so far.

src/command/cmd_ac.c

@@ -3765,9 +3765,8 @@ _correct_autocomplete(ProfWin *window, const char *const input, gboolean previou
 		return NULL;
 	}
 
-	GString *result_str = g_string_new("/correct \"");
+	GString *result_str = g_string_new("/correct ");
 	g_string_append(result_str, last_message);
-	g_string_append(result_str, "\"");
 	char *result = result_str->str;
 	g_string_free(result_str, FALSE);