add Field.component_name and Field.grid_name to reference.dox

doc/src/reference.dox

@@ -547,6 +547,8 @@
       <li> \ref yac.Field.name
       <li> \ref yac.Field.timestep
       <li> \ref yac.Field.collection_size
+      <li> \ref yac.Field.component_name
+      <li> \ref yac.Field.grid_name
   <tr>
     <td style="vertical-align:top;width:33%">
       <ul style="margin-top:5px;margin-bottom:5px">