Update docstrings for Numba reducer functions

aesara/link/numba/dispatch.py

@@ -505,13 +505,35 @@ def create_axis_reducer(
     dtype: numba.types.Type,
     keepdims: bool = False,
 ) -> numba.core.dispatcher.Dispatcher:
-    """Create a Numba JITed function that performs a NumPy reduction on a given axis.
+    r"""Create a Numba JITed function that performs a NumPy reduction on a given axis.
+
+    The functions generated by this function take the following form:
+
+    .. code-block:: python
+
+        def careduce_axis(x):
+            res_shape = tuple(shape[i] if i < axis else shape[i + 1] for i in range(ndim - 1))
+            res = np.full(res_shape, identity, dtype=dtype)
+
+            x_axis_first = x.transpose(reaxis_first)
+
+            for m in range(x.shape[axis]):
+                reduce_fn(res, x_axis_first[m], res)
+
+            if keepdims:
+                return np.expand_dims(res, axis)
+            else:
+                return res
+
+
+    This can be removed/replaced when
+    https://github.com/numba/numba/issues/4504 is implemented.
 
     Parameters
     ==========
     reduce_fn:
         The Numba ``ufunc`` representing a binary op that can perform the
-        reduction on arbitrary ``ndarray``s.
+        reduction on arbitrary ``ndarray``\s.
     identity:
         The identity value for the reduction.
     axis:
@@ -581,6 +603,38 @@ def create_axis_reducer(
 def create_multiaxis_reducer(
     reduce_fn, identity, axes, ndim, dtype, input_name="input"
 ):
+    r"""Construct a function that reduces multiple axes.
+
+    The functions generated by this function take the following form:
+
+    .. code-block:: python
+
+        def careduce_maximum(input):
+            axis_0_res = careduce_axes_fn_0(input)
+            axis_1_res = careduce_axes_fn_1(axis_0_res)
+            ...
+            axis_N_res = careduce_axes_fn_N(axis_N_minus_1_res)
+            return axis_N_res
+
+    The range 0-N is determined by the `axes` argument (i.e. the
+    axes to be reduced).
+
+
+    Parameters
+    ==========
+    reduce_fn:
+        The Numba ``ufunc`` representing a binary op that can perform the
+        reduction on arbitrary ``ndarray``\s.
+    identity:
+        The identity value for the reduction.
+    axes:
+        The axes to reduce.
+    ndim:
+        The number of dimensions of the result.
+    dtype:
+        The data type of the result.
+
+    """
     if len(axes) == 1:
         return create_axis_reducer(reduce_fn, identity, axes[0], ndim, dtype)