patch 8.0.0836: can abandon a terminal buffer after making a change

Problem:    When a terminal buffer is changed it can still be accidentally
            abandoned.
Solution:   When making a change reset the 'buftype' option.

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    836,
 /**/
     835,
 /**/