patch 8.2.4911: the mode #defines are not clearly named

Problem:    The mode #defines are not clearly named.
Solution:   Prepend MODE_.  Renumber them to put the mapped modes first.
diff --git a/src/menu.c b/src/menu.c
index 2af54a7..3c4236b 100644
--- a/src/menu.c
+++ b/src/menu.c
@@ -1754,9 +1754,9 @@
 {
     int		idx;
 
-    if ((state & INSERT))
+    if ((state & MODE_INSERT))
 	idx = MENU_INDEX_INSERT;
-    else if (state & CMDLINE)
+    else if (state & MODE_CMDLINE)
 	idx = MENU_INDEX_CMDLINE;
 #ifdef FEAT_TERMINAL
     else if (term_use_loop())
@@ -1769,11 +1769,11 @@
 	else
 	    idx = MENU_INDEX_VISUAL;
     }
-    else if (state == HITRETURN || state == ASKMORE)
+    else if (state == MODE_HITRETURN || state == MODE_ASKMORE)
 	idx = MENU_INDEX_CMDLINE;
     else if (finish_op)
 	idx = MENU_INDEX_OP_PENDING;
-    else if ((state & NORMAL))
+    else if ((state & MODE_NORMAL))
 	idx = MENU_INDEX_NORMAL;
     else
 	idx = MENU_INDEX_INVALID;
@@ -1929,15 +1929,16 @@
 	    return MENU_INDEX_SELECT;
 	return MENU_INDEX_VISUAL;
     }
-    if (State & INSERT)
+    if (State & MODE_INSERT)
 	return MENU_INDEX_INSERT;
-    if ((State & CMDLINE) || State == ASKMORE || State == HITRETURN)
+    if ((State & MODE_CMDLINE) || State == MODE_ASKMORE
+						    || State == MODE_HITRETURN)
 	return MENU_INDEX_CMDLINE;
     if (finish_op)
 	return MENU_INDEX_OP_PENDING;
-    if (State & NORMAL)
+    if (State & MODE_NORMAL)
 	return MENU_INDEX_NORMAL;
-    if (State & LANGMAP)	// must be a "r" command, like Insert mode
+    if (State & MODE_LANGMAP)	// must be a "r" command, like Insert mode
 	return MENU_INDEX_INSERT;
     return MENU_INDEX_INVALID;
 }