Fix article in comment (very minor)
diff --git a/src/write.c b/src/write.c
index adb4151..2068fff 100644
--- a/src/write.c
+++ b/src/write.c
@@ -575,7 +575,7 @@
// so there must still be a primary item pointing at a sync sample. Since the first
// frame of the image sequence is guaranteed to be a sync sample, it is chosen here.
//
- // TODO: Offer the ability for an user to specify which frame in the sequence should
+ // TODO: Offer the ability for a user to specify which frame in the sequence should
// become the primary item's image, and force that frame to be a keyframe.
contentSize = (uint32_t)item->encodeOutput->samples.sample[0].data.size;
}