Updated docs for randint operator

docs/api/python/ndarray/ndarray.md

@@ -596,6 +596,7 @@ The `ndarray` package provides several classes:
     mxnet.ndarray.random.generalized_negative_binomial
     mxnet.ndarray.random.multinomial
     mxnet.ndarray.random.shuffle
+    mxnet.ndarray.random.randint
     mxnet.random.seed
 ```
 

docs/api/python/ndarray/random.md

@@ -37,6 +37,7 @@ In the rest of this document, we list routines provided by the `ndarray.random`
     uniform
     multinomial
     shuffle
+    randint
     mxnet.random.seed
 ```
 

docs/api/python/symbol/random.md

@@ -37,6 +37,7 @@ In the rest of this document, we list routines provided by the `symbol.random` p
     uniform
     multinomial
     shuffle
+    randint
     mxnet.random.seed
 ```
 

docs/api/python/symbol/symbol.md

@@ -595,6 +595,7 @@ Composite multiple symbols into a new one by an operator.
     mxnet.symbol.random.generalized_negative_binomial
     mxnet.symbol.random.multinomial
     mxnet.symbol.random.shuffle
+    mxnet.symbol.random.randint
     mxnet.random.seed
 ```