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_bc5.mak b/src/Make_bc5.mak
index 7b5b0f2..1c13931 100644
--- a/src/Make_bc5.mak
+++ b/src/Make_bc5.mak
@@ -534,6 +534,7 @@
 	$(OBJDIR)\hardcopy.obj \
 	$(OBJDIR)\hashtab.obj \
 	$(OBJDIR)\indent.obj \
+	$(OBJDIR)\insexpand.obj \
 	$(OBJDIR)\json.obj \
 	$(OBJDIR)\list.obj \
 	$(OBJDIR)\main.obj \