mismatch between ec_dec_uint doc and code

[est31]

Minor nit.

In the documentation of the ec_dec_uint function, there is a note that the param "must be at least one, and no more than 2**32-1", so >= 1. In the implementation of the function we have the following:

opus_uint32 ec_dec_uint(ec_dec *_this,opus_uint32 _ft){
  /* [...] */
  /*In order to optimize EC_ILOG(), it is undefined for the value 0.*/
  celt_assert(_ft>1);

... so requiring >1 for the param.

[jmvalin]

Doc fixed (assert was correct)