Remove docstring of non-existent method (#1962)

entropy(::UnivariateDistribution, ::Bool) falls back to entropy(::UnivariateDistribution, ::Real), and the docstrings are just duplicated

Author: abhro

docs/src/univariate.md

@@ -59,7 +59,6 @@ isplatykurtic(::UnivariateDistribution)
 isleptokurtic(::UnivariateDistribution)
 ismesokurtic(::UnivariateDistribution)
 entropy(::UnivariateDistribution)
-entropy(::UnivariateDistribution, ::Bool)
 entropy(::UnivariateDistribution, ::Real)
 mgf(::UnivariateDistribution, ::Any)
 cgf(::UnivariateDistribution, ::Any)