patch 9.0.0275: BufEnter not triggered when using ":edit" in "nofile" buffer

Problem:    BufEnter not triggered when using ":edit" in "nofile" buffer.
Solution:   Let readfile() return NOTDONE. (closes #10986)
diff --git a/src/version.c b/src/version.c
index 9590974..e32f990 100644
--- a/src/version.c
+++ b/src/version.c
@@ -724,6 +724,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    275,
+/**/
     274,
 /**/
     273,