patch 8.0.0388: filtering lines changes folds

Problem:    filtering lines through "cat", without changing the line count,
            changes manual folds.
Solution:   Change how marks and folds are adjusted. (Matthew Malcomson, from
            neovim #6194.
diff --git a/src/version.c b/src/version.c
index a0396d1..19d3322 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    388,
+/**/
     387,
 /**/
     386,