also support unions and groups

Author: dwrensha

capnpc/rust.capnp

@@ -1,6 +1,6 @@
 @0x83b3c14c3c8dd083;
 
-annotation name @0xc2fe4c6d100166d0 (field, struct, enum, enumerant) :Text;
+annotation name @0xc2fe4c6d100166d0 (field, struct, enum, enumerant, union, group) :Text;
 # Rename something in the generated code. The value that you specify in this
 # annotion must follow capnp capitalization conventions. So, for example,
 # a struct could be named `StructFoo`, even though that will get translated

capnpc/test/test.capnp

@@ -771,4 +771,12 @@ struct TestNameAnnotation $Rust.name("RenamedStruct") {
       grault @2 $Rust.name("garply");
     }
   }
+
+  badlyNamedUnion :union $Rust.name("renamedUnion") {
+    badlyNamedGroup :group $Rust.name("renamedGroup") {
+      foo @3 :Void;
+      bar @4 :Void;
+    }
+    baz @5 :NestedStruct $Rust.name("qux");
+  }
 }

capnpc/test/test.rs

@@ -1482,6 +1482,9 @@ mod tests {
             let mut root: renamed_struct::Builder = message.init_root();
             root.set_good_field_name(true);
             root.set_another_good_field_name(renamed_struct::RenamedEnum::Bar);
+
+            let renamed_union = root.get_renamed_union();
+            renamed_union.init_qux();
         }
         {
             let root: renamed_struct::Reader = message.get_root_as_reader().unwrap();
@@ -1490,6 +1493,12 @@ mod tests {
                 _ => panic!("expected GoodFieldName(true)"),
             }
             assert!(renamed_struct::RenamedEnum::Bar == root.get_another_good_field_name().unwrap());
+
+
+            match root.get_renamed_union().which().unwrap() {
+                renamed_struct::renamed_union::Qux(_) => (),
+                _ => panic!("expected Qux"),
+            }
         }
     }
 }