Correct a documentation error. (#209)

Author: dmbates

docs/src/functions_overview.md

@@ -20,7 +20,7 @@ Here the *Special Functions* are listed according to the structure of [NIST Digi
 | [`beta(x,y)`](@ref SpecialFunctions.beta)                                           | [beta function](https://en.wikipedia.org/wiki/Beta_function) at `x,y`                                                                                           |
 | [`logbeta(x,y)`](@ref SpecialFunctions.logbeta)                                          | accurate `log(beta(x,y))` for large `x` or `y`      |
 | [`logabsbeta(x,y)`](@ref SpecialFunctions.logabsbeta)                                          | accurate `log(abs(beta(x,y)))` for large `x` or `y`     |
-| [`logabsbinomial(x,y)`](@ref SpecialFunctions.logabsbinomial)                                          | accurate `log(abs(beta(x,y)))` for large `x` or `y`     |
+| [`logabsbinomial(x,y)`](@ref SpecialFunctions.logabsbinomial)                                          | accurate `log(abs(binomial(n,k)))` for large `n` and `k` near `n/2`     |
 
 
 ## [Trigonometric Integrals](https://dlmf.nist.gov/6)