Fix stream related spelling mistakes

Remove double "is".
Consistent spelling of all-uppercase I/O.
Signed-off-by: NPhilipp Hahn <hahn@univention.de>

src/libvirt.c

@@ -15890,7 +15890,7 @@ error:
  *
  * Send the entire data stream, reading the data from the
  * requested data source. This is simply a convenient alternative
- * to virStreamSend, for apps that do blocking-I/o.
+ * to virStreamSend, for apps that do blocking-I/O.
  *
  * An example using this with a hypothetical file upload
  * API looks like
@@ -15983,7 +15983,7 @@ cleanup:
  *
  * Receive the entire data stream, sending the data to the
  * requested data sink. This is simply a convenient alternative
- * to virStreamRecv, for apps that do blocking-I/o.
+ * to virStreamRecv, for apps that do blocking-I/O.
  *
  * An example using this with a hypothetical file download
  * API looks like
@@ -16192,7 +16192,7 @@ error:
  * virStreamFinish:
  * @stream: pointer to the stream object
  *
- * Indicate that there is no further data is to be transmitted
+ * Indicate that there is no further data to be transmitted
  * on the stream. For output streams this should be called once
  * all data has been written. For input streams this should be
  * called once virStreamRecv returns end-of-file.