Fix several typos (#1169)

Co-authored-by: isaacw <isaacw@nvidia.com>

examples/python/04_epilogue_visitor.ipynb

@@ -68,7 +68,7 @@
    "source": [
     "## Define the epilogue visitor functor\n",
     "The epilogue functor can be defined as a simple Python function and a set of example tensors for inputs and outputs. The example below illustrates a complex epilogue under the directed acyclic graph structure (`F` is used twice). The epilogue takes source tensors in different ranks: `alpha`, `beta` are scalars, `bias` is a column vector to broadcast, and `C`, `aux` are matrices. It contains various math operations from basic arithmatic operations and built-in callable functions like `relu`. It also accomodates multiple outputs `D` and `F`. Note that there are some restrictions on syntax.\n",
-    "* Each named variable must be assigned exactly once and defined before it it used.\n",
+    "* Each named variable must be assigned exactly once and defined before it used.\n",
     "* Reserved names: `accum`, `C`, and `D` are reserved for accumulator, tensor_C, and tensor_D.\n",
     "* Return values must be a named variable.\n",
     "\n",