patch 8.1.1901: the +insert_expand feature is not always available

Problem:    The +insert_expand feature is not always available.
Solution:   Graduate the +insert_expand feature.
diff --git a/src/vim.h b/src/vim.h
index 631a57d..4a86177 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -848,9 +848,7 @@
 #define ACTION_GOTO	2
 #define ACTION_SPLIT	3
 #define ACTION_SHOW_ALL	4
-#ifdef FEAT_INS_EXPAND
-# define ACTION_EXPAND	5
-#endif
+#define ACTION_EXPAND	5
 
 #ifdef FEAT_SYN_HL
 # define SST_MIN_ENTRIES 150	/* minimal size for state stack array */