patch 8.2.2905: no error when defaults.vim cannot be loaded

Problem:    No error when defaults.vim cannot be loaded.
Solution:   Add an error message. (Christian Brabandt, closes #8248)
diff --git a/src/version.c b/src/version.c
index b95a969..ca90eea 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2905,
+/**/
     2904,
 /**/
     2903,