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/Make_ivc.mak b/src/Make_ivc.mak
index 0691e8d..27b2c33 100644
--- a/src/Make_ivc.mak
+++ b/src/Make_ivc.mak
@@ -235,6 +235,7 @@
 	"$(INTDIR)/hardcopy.obj" \
 	"$(INTDIR)/hashtab.obj" \
 	"$(INTDIR)/indent.obj" \
+	"$(INTDIR)/insexpand.obj" \
 	"$(INTDIR)/json.obj" \
 	"$(INTDIR)/list.obj" \
 	"$(INTDIR)/main.obj" \
@@ -439,6 +440,10 @@
 SOURCE=.\indent.c
 # End Source File
 # Begin Source File
+#
+SOURCE=.\insexpand.c
+# End Source File
+# Begin Source File
 
 SOURCE=.\gui.c