Fix spelling of "length".
diff --git a/xmlreader.c b/xmlreader.c
index 579e943..2c2a683 100644
--- a/xmlreader.c
+++ b/xmlreader.c
@@ -984,7 +984,7 @@
  * xmlTextReaderValidateCData:
  * @reader:  the xmlTextReaderPtr used
  * @data:  pointer to the CData
- * @len:  lenght of the CData block in bytes.
+ * @len:  length of the CData block in bytes.
  *
  * Push some CData for validation
  */