Docbug: Replace opus_encode_frame with opus_encode_float in doxygen.

include/opus.h

@@ -139,7 +139,7 @@ extern "C" {
   * <li>max_packet is the maximum number of bytes that can be written in the packet (4000 bytes is recommended)</li>
   * </ul>
   *
-  * opus_encode() and opus_encode_frame() return the number of bytes actually written to the packet.
+  * opus_encode() and opus_encode_float() return the number of bytes actually written to the packet.
   * The return value <b>can be negative</b>, which indicates that an error has occurred. If the return value
   * is 1 byte, then the packet does not need to be transmitted (DTX).
   *