[cairo] Doc fix
diff --git a/src/hb-cairo.cc b/src/hb-cairo.cc
index 63d924f..d988267 100644
--- a/src/hb-cairo.cc
+++ b/src/hb-cairo.cc
@@ -675,7 +675,7 @@
* @buffer: a `hb_buffer_t` containing glyphs
* @text: (nullable): the text that was shaped in @buffer
* @text_len: the length of @text in bytes
- * @utf8_clusters: `true` to provide cluster positions in bytes, instead of characters
+ * @utf8_clusters: `true` to if @buffer clusters are in bytes, instead of characters
* @scale_factor: scale factor to divide hb_positions_t values by
* @glyphs: return location for an array of `cairo_glyph_t`
* @num_glyphs: return location for the length of @glyphs
