patch 9.0.1213: adding a line below the last one does not expand fold

Problem:    Adding a line below the last one does not expand fold.
Solution:   Do not skip mark_adjust() when adding lines below the last one.
            (Brandon Simmons, closes #11832, closes #10698)
diff --git a/src/change.c b/src/change.c
index dc68d3c..1e7bdd6 100644
--- a/src/change.c
+++ b/src/change.c
@@ -772,14 +772,7 @@
     void
 appended_lines_mark(linenr_T lnum, long count)
 {
-    // Skip mark_adjust when adding a line after the last one, there can't
-    // be marks there. But it's still needed in diff mode.
-    if (lnum + count < curbuf->b_ml.ml_line_count
-#ifdef FEAT_DIFF
-	    || curwin->w_p_diff
-#endif
-	)
-	mark_adjust(lnum + 1, (linenr_T)MAXLNUM, count, 0L);
+    mark_adjust(lnum + 1, (linenr_T)MAXLNUM, count, 0L);
     changed_lines(lnum + 1, 0, lnum + 1, count);
 }
 
@@ -2142,14 +2135,7 @@
 	    goto theend;
 	// Postpone calling changed_lines(), because it would mess up folding
 	// with markers.
-	// Skip mark_adjust when adding a line after the last one, there can't
-	// be marks there. But still needed in diff mode.
-	if (curwin->w_cursor.lnum + 1 < curbuf->b_ml.ml_line_count
-#ifdef FEAT_DIFF
-		|| curwin->w_p_diff
-#endif
-	    )
-	    mark_adjust(curwin->w_cursor.lnum + 1, (linenr_T)MAXLNUM, 1L, 0L);
+	mark_adjust(curwin->w_cursor.lnum + 1, (linenr_T)MAXLNUM, 1L, 0L);
 	did_append = TRUE;
 #ifdef FEAT_PROP_POPUP
 	if ((State & MODE_INSERT) && (State & VREPLACE_FLAG) == 0)