patch 8.2.3907: error messages are spread out

Problem:    Error messages are spread out.
Solution:   Move error messages to errors.h.  Avoid duplicates.
diff --git a/src/version.c b/src/version.c
index 8b9b27e..7b8b0a6 100644
--- a/src/version.c
+++ b/src/version.c
@@ -750,6 +750,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3907,
+/**/
     3906,
 /**/
     3905,