Rename misc uses of "free"
In preparation for fixing https://github.com/harfbuzz/harfbuzz/issues/3044
diff --git a/src/hb-iter.hh b/src/hb-iter.hh
index f701815..b8c4472 100644
--- a/src/hb-iter.hh
+++ b/src/hb-iter.hh
@@ -46,7 +46,7 @@
* TODO Document more.
*
* If iterator implementation implements operator!=, then can be
- * used in range-based for loop. That comes free if the iterator
+ * used in range-based for loop. That already happens if the iterator
* is random-access. Otherwise, the range-based for loop incurs
* one traversal to find end(), which can be avoided if written
* as a while-style for loop, or if iterator implements a faster
