patch 8.0.0448: some macros are in lower case

Problem:    Some macros are in lower case, which can be confusing.
Solution:   Make a few lower case macros upper case.
diff --git a/src/fold.c b/src/fold.c
index d75e937..db8da63 100644
--- a/src/fold.c
+++ b/src/fold.c
@@ -1039,7 +1039,7 @@
     if (!VIsual_active || !hasAnyFolding(curwin))
 	return;
 
-    if (ltoreq(VIsual, curwin->w_cursor))
+    if (LTOREQ_POS(VIsual, curwin->w_cursor))
     {
 	start = &VIsual;
 	end = &curwin->w_cursor;