Patch CDF equation HurdleNegativeBinomial (#96)

* fix equation for CDF of HurdleNegativeBinomial (analogous to fix of HurdlePoisson by @dkwhu)

* re-run devtools::document() for updated in CDF equation in HurdlePoisson and HurdleNegativeBinomial

* include CDF fixes in NEWS

NEWS.md

@@ -1,5 +1,9 @@
 # distributions3 (development version)
 
+- Fixed errors in notation of cumulative distribution function in the documentation of
+  `HurdlePoisson()` and `HurdleNegativeBinomial()` (by @dkwhu in #94 and #96).
+
+
 # distributions3 0.2.1
 
 - New generics `is_discrete()` and `is_continous()` with methods for all distribution objects

R/HurdleNegativeBinomial.R

@@ -153,9 +153,9 @@ rhnbinom <- function(n, mu, theta, size, pi) {
 #'   **Cumulative distribution function (c.d.f.)**: \eqn{P(X \le 0) = 1 - \pi} and for \eqn{k > 0}
 #'
 #'   \deqn{
-#'     P(X = k) = 1 - \pi + \pi \cdot \frac{F(k; \mu, \theta)}{1 - F(0; \mu, \theta)}
+#'     P(X \le k) = 1 - \pi + \pi \cdot \frac{F(k; \mu, \theta) - F(0; \mu, \theta)}{1 - F(0; \mu, \theta)}
 #'   }{
-#'     P(X = k) = 1 - \pi + \pi \cdot F(k; \mu, \theta)/(1 - F(0; \mu, \theta))
+#'     P(X \le k) = 1 - \pi + \pi \cdot (F(k; \mu, \theta) - F(0; \mu, \theta))/(1 - F(0; \mu, \theta))
 #'   }
 #'
 #'   **Moment generating function (m.g.f.)**: