Fix docstring for gamma_inc.rgamma1pm1 (#469)

Author: abhro

src/gamma_inc.jl

@@ -33,8 +33,8 @@ const d80 = -.652623918595309E-03
 """
    rgamma1pm1(a)
 
-   Computation of ``1/Gamma(a+1) - 1`` for `-0.5<=a<=1.5` : ``1/\\Gamma (a+1) - 1``
-   Uses the relation `gamma(a+1) = a*gamma(a)`.
+Computation of ``1/Gamma(a+1) - 1`` for `-0.5<=a<=1.5` : ``1/\\Gamma (a+1) - 1``
+Uses the relation `gamma(a+1) = a*gamma(a)`.
 """
 function rgamma1pm1(a::Float64)
     @assert -0.5 <= a <= 1.5