patch 8.2.0674: some source files are too big

Problem:    Some source files are too big.
Solution:   Move text formatting functions to a new file. (Yegappan
            Lakshmanan, closes #6021)
diff --git a/src/Make_cyg_ming.mak b/src/Make_cyg_ming.mak
index 7964b0a..94561e5 100644
--- a/src/Make_cyg_ming.mak
+++ b/src/Make_cyg_ming.mak
@@ -787,6 +787,7 @@
 	$(OUTDIR)/tag.o \
 	$(OUTDIR)/term.o \
 	$(OUTDIR)/testing.o \
+	$(OUTDIR)/textformat.o \
 	$(OUTDIR)/textobject.o \
 	$(OUTDIR)/textprop.o \
 	$(OUTDIR)/time.o \