patch 8.1.1076: file for Insert mode is much too big

Problem:    File for Insert mode is much too big.
Solution:   Split off the code for Insert completion. (Yegappan Lakshmanan,
            closes #4044)
diff --git a/src/Makefile b/src/Makefile
index 5fa3790..35471ae 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -1599,6 +1599,7 @@
 	if_cscope.c \
 	if_xcmdsrv.c \
 	indent.c \
+	insexpand.c \
 	json.c \
 	list.c \
 	main.c \
@@ -1713,6 +1714,7 @@
 	objects/if_cscope.o \
 	objects/if_xcmdsrv.o \
 	objects/indent.o \
+	objects/insexpand.o \
 	objects/list.o \
 	objects/mark.o \
 	objects/memline.o \
@@ -1844,6 +1846,7 @@
 	if_ruby.pro \
 	if_xcmdsrv.pro \
 	indent.pro \
+	insexpand.pro \
 	json.pro \
 	list.pro \
 	main.pro \
@@ -3098,6 +3101,9 @@
 objects/indent.o: indent.c
 	$(CCC) -o $@ indent.c
 
+objects/insexpand.o: insexpand.c
+	$(CCC) -o $@ insexpand.c
+
 objects/json.o: json.c
 	$(CCC) -o $@ json.c
 
@@ -3500,6 +3506,10 @@
  auto/osdef.h ascii.h keymap.h term.h macros.h option.h beval.h \
  proto/gui_beval.pro structs.h regexp.h gui.h alloc.h ex_cmds.h spell.h \
  proto.h globals.h
+objects/insexpand.o: insexpand.c vim.h protodef.h auto/config.h feature.h \
+ os_unix.h auto/osdef.h ascii.h keymap.h term.h macros.h option.h beval.h \
+ proto/gui_beval.pro structs.h regexp.h gui.h alloc.h ex_cmds.h spell.h \
+ proto.h globals.h
 objects/json.o: json.c vim.h protodef.h auto/config.h feature.h os_unix.h \
  auto/osdef.h ascii.h keymap.h term.h macros.h option.h beval.h \
  proto/gui_beval.pro structs.h regexp.h gui.h alloc.h ex_cmds.h spell.h \