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)
diff --git a/src/register.c b/src/register.c
index bc687c0..3454cfa 100644
--- a/src/register.c
+++ b/src/register.c
@@ -2208,15 +2208,7 @@
 		if (dir == FORWARD)
 		    curbuf->b_op_start.lnum++;
 	    }
-	    // Skip mark_adjust when adding lines after the last one, there
-	    // can't be marks there. But still needed in diff mode.
-	    if (curbuf->b_op_start.lnum + (y_type == MCHAR) - 1 + nr_lines
-						 < curbuf->b_ml.ml_line_count
-#ifdef FEAT_DIFF
-						 || curwin->w_p_diff
-#endif
-						 )
-		mark_adjust(curbuf->b_op_start.lnum + (y_type == MCHAR),
+	    mark_adjust(curbuf->b_op_start.lnum + (y_type == MCHAR),
 					     (linenr_T)MAXLNUM, nr_lines, 0L);
 
 	    // note changed text for displaying and folding
diff --git a/src/testdir/test_fold.vim b/src/testdir/test_fold.vim
index f915a66..7f75e91 100644
--- a/src/testdir/test_fold.vim
+++ b/src/testdir/test_fold.vim
Binary files differ
diff --git a/src/version.c b/src/version.c
index 3496b3a..ae5de35 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1213,
+/**/
     1212,
 /**/
     1211,