[Doc] Quick Fix doc (#820)

* fix doc

* poke ci

* poke ci

* upd

* fix doc

* upd

* add title for all nn

* upd

* fix warning

* fix

python/dgl/nn/mxnet/conv.py

@@ -386,7 +386,7 @@ class RelGraphConv(gluon.Block):
         return {'msg': msg}
 
     def forward(self, g, x, etypes, norm=None):
-        """Forward computation
+        r"""Forward computation
 
         Parameters
         ----------
@@ -394,13 +394,13 @@ class RelGraphConv(gluon.Block):
             The graph.
         x : mx.ndarray.NDArray
             Input node features. Could be either
-              - (|V|, D) dense tensor
-              - (|V|,) int64 vector, representing the categorical values of each
+              - :math:`(|V|, D)` dense tensor
+              - :math:`(|V|,)` int64 vector, representing the categorical values of each
                 node. We then treat the input feature as an one-hot encoding feature.
         etypes : mx.ndarray.NDArray
-            Edge type tensor. Shape: (|E|,)
+            Edge type tensor. Shape: :math:`(|E|,)`
         norm : mx.ndarray.NDArray
-            Optional edge normalizer tensor. Shape: (|E|, 1)
+            Optional edge normalizer tensor. Shape: :math:`(|E|, 1)`
 
         Returns
         -------

python/dgl/nn/pytorch/factory.py

@@ -44,7 +44,8 @@ class KNNGraph(nn.Module):
 
         Returns
         -------
-        A DGLGraph with no features.
+        DGLGraph
+            A DGLGraph with no features.
         """
         return knn_graph(x, self.k)
 
@@ -65,19 +66,6 @@ class SegmentedKNNGraph(nn.Module):
     ----------
     k : int
         The number of neighbors
-
-    Inputs
-    ------
-    x : Tensor
-        :math:`(M, D)` where :math:`M` means the total number of points
-        in all point sets.
-    segs : Tensor
-        :math:`(N)` integer tensors where :math:`N` means the number of
-        point sets.  The elements must sum up to :math:`M`.
-
-    Outputs
-    -------
-    - A DGLGraph with no features.
     """
     def __init__(self, k):
         super(SegmentedKNNGraph, self).__init__()
@@ -98,6 +86,7 @@ class SegmentedKNNGraph(nn.Module):
 
         Returns
         -------
-        A DGLGraph with no features.
+        DGLGraph
+            A DGLGraph with no features.
         """
         return segmented_knn_graph(x, self.k, segs)