Minor documentation fixes and improvements.
diff --git a/include/freetype/freetype.h b/include/freetype/freetype.h
index ad9610d..b70fcd5 100644
--- a/include/freetype/freetype.h
+++ b/include/freetype/freetype.h
@@ -2099,7 +2099,8 @@ FT_BEGIN_HEADER
* The size in bytes of the file in memory.
*
* pathname ::
- * A pointer to an 8-bit file pathname. The pointer is not owned by
+ * A pointer to an 8-bit file pathname, which must be a C~string (i.e.,
+ * no NULL bytes except at the very end). The pointer is not owned by
* FreeType.
*
* stream ::
@@ -2186,9 +2187,12 @@ FT_BEGIN_HEADER
* FreeType error code. 0~means success.
*
* @note:
- * The `pathname` string should be reconizable as such by a standard
- * `fopen()` call on your system. If that is not sufficient to address
- * all file name possiblities, you can use @FT_Open_Face.
+ * The `pathname` string should be recognizable as such by a standard
+ * `fopen` call on your system; in particular, this means that `pathname`
+ * must not contain NULL bytes. If that is not sufficient to address all
+ * file name possibilities (for example, to handle wide character file
+ * names on Windows in UTF-16 encoding) you might use @FT_Open_Face to
+ * pass a memory array or a stream object instead.
*
* Use @FT_Done_Face to destroy the created @FT_Face object (along with
* its slot and sizes).