itree.c and buffer-tests.el: Incorporate code review feedback

* src/itree.c: Improve wording in `itree_insert_gap` comment.
* test/src/buffer-tests.el (test-overlay-insert-before-markers-at-start):
Don't rely on (point-min) being 1.
(test-overlay-insert-before-markers-at-end): ditto.
(test-overlay-insert-before-markers-empty): ditto.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/itree.c b/src/itree.c
index 989f452cb92..d73fbffd2b6 100644
--- a/src/itree.c
+++ b/src/itree.c
@@ -1193,8 +1193,8 @@ itree_iterator_finish (struct itree_iterator *iter)
    intersecting it, while respecting their rear_advance and
    front_advance setting.
 
-   When BEFORE_MARKERS, all overlays beginning/ending at POS are
-   treated as if their front_advance/rear_advance was true. */
+   If BEFORE_MARKERS is non-zero, all overlays beginning/ending at POS
+   are treated as if their front_advance/rear_advance was true. */
 
 void
 itree_insert_gap (struct itree_tree *tree,