Add mixed topology examples from Ascent tests (#1285)

CHANGELOG.md

@@ -22,6 +22,9 @@ and this project aspires to adhere to [Semantic Versioning](https://semver.org/s
 - Fixed partitioner so it reverses vertex order as needed in polyhedral face definitions when extracting mesh elements.
 - Changed `conduit::blueprint::mesh::partition_map_back()` function so it will attempt to reuse existing field memory when mapping fields back. This permits `partition_map_back()` to send data from a partitioned mesh into the original mesh where fields were provided from a host code using `Node::set_external()`.
 - Changed `generate_sides` to be robust to the case where no fields exist. 
+- Deprecated braid `quads_and_tris` example in favor of `mixed_2d`.
+- Deprecated braid `braid_quads_and_tris_offsets` example in favor of `mixed_2d`.
+- Deprecated braid `hexs_and_tris` example in favor of `mixed`.
 
 #### Relay
 - Changed `conduit::relay::mpi::communicate_using_schema` to avoid an invalid tag MPI error message on some MPI distributions.

src/libs/blueprint/conduit_blueprint_mesh_examples.cpp

@@ -1624,9 +1624,13 @@ braid_quads(index_t npts_x,
 //---------------------------------------------------------------------------//
 void
 braid_quads_and_tris(index_t npts_x,
-            index_t npts_y,
-            Node &res)
+                     index_t npts_y,
+                     Node &res)
 {
+    CONDUIT_INFO("This braid example is deprecated in favor of mixed_2d.")
+
+    // TODO remove in conduit 0.9.4
+
     res.reset();
 
     int32 nele_x = (int32)(npts_x - 1);
@@ -1675,7 +1679,6 @@ braid_quads_and_tris(index_t npts_x,
              ++ielem;
 
         } // END for all i
-
     } // END for all j
 
 
@@ -1744,12 +1747,16 @@ braid_quads_and_tris(index_t npts_x,
     //                                         fields["radial"]);
 }
 
+
 //---------------------------------------------------------------------------//
 void
 braid_quads_and_tris_offsets(index_t npts_x,
                              index_t npts_y,
                              Node &res)
 {
+    CONDUIT_INFO("This braid example is deprecated in favor of mixed_2d.")
+
+    // TODO remove in conduit 0.9.4
 
     res.reset();
 
@@ -2650,6 +2657,9 @@ braid_hexs_and_tets(index_t npts_x,
                     index_t npts_z,
                     Node &res)
 {
+    CONDUIT_INFO("This braid example is deprecated in favor of mixed.")
+
+    // TODO remove in conduit 0.9.4
 
     // WARNING -- The code below is UNTESTED.
     //            The SILO writer is missing an implementation for