message: Update storage docs for reading complete headers
diff: @@ -1603,8 +1603,8 @@ impl Storage {
  .transpose()
  }
  - /// Retrieves a single complete block header by height by looking it up in
  - /// the index and returning it.
  + /// Retrieves a single block header by height from the available block
  + /// range by looking it up in the index and returning it.
  pub fn read_complete_block_header_by_height(
  &self,
  height: u64,
  