[Doc] Updated transform ops list in dgl.rst (Issue #4087) (#4123)

* * Added functions from dgl.transforms.functional that were missing from the list for documentation in dgl.rst

* * Sorted transform ops list in dgl.rst in alphabetical order
Co-authored-by: Xin Yao <xiny@nvidia.com>

docs/source/api/python/dgl.rst

@@ -60,29 +60,47 @@ Operators for generating new graphs by manipulating the structure of the existin
 .. autosummary::
     :toctree: ../../generated/
 
-    add_nodes
     add_edges
-    remove_nodes
-    remove_edges
+    add_nodes
+    add_reverse_edges
     add_self_loop
+    adj_product_graph
+    adj_sum_graph
+    as_heterograph
+    as_immutable_graph
+    compact_graphs
+    khop_adj
+    khop_graph
+    knn_graph
+    laplacian_lambda_max
+    laplacian_pe
+    line_graph
+    metapath_reachable_graph
+    metis_partition
+    metis_partition_assignment
+    norm_by_dst
+    partition_graph_with_halo
+    radius_graph
+    random_walk_pe
+    remove_edges
+    remove_nodes
     remove_self_loop
-    add_reverse_edges
+    reorder_graph
     reverse
+    segmented_knn_graph
+    sort_csr_by_tag
+    sort_csc_by_tag
     to_bidirected
-    to_simple
+    to_bidirected_stale
     to_block
-    compact_graphs
+    to_double
+    to_float
+    to_half
     to_heterogeneous
     to_homogeneous
     to_networkx
-    line_graph
-    khop_graph
-    metapath_reachable_graph
-    adj_product_graph
-    adj_sum_graph
-    reorder_graph
-    sort_csr_by_tag
-    sort_csc_by_tag
+    to_simple
+    to_simple_graph
 
 .. _api-positional-encoding: