message: [pdsl_core] Make RawChunkCell and TypedChunkCell pub(crate)
  They are going to be used by MutChunk.
diff: @@ -7,6 +7,11 @@ mod typed_chunk;
  mod copy_chunk;
  mod mut_chunk;
  +pub(crate) use self::{
  + raw_chunk::RawChunkCell,
  + typed_chunk::TypedChunkCell,
  +};
  +
  pub use self::{
  raw_chunk::RawChunk,
  typed_chunk::TypedChunk,
  