## 4.0.0

- Made document search asynchronous to search field input, so UI remains
  smooth even if search is slow

- Added status to search bar:

    - `OK` means Docfd is idling
    - `...` means Docfd is searching
    - `ERR` means Docfd failed to parse the search expression

- Added search cancellation. Triggered by editing or clearing search field.

- Added dynamic search distance adjustment based on notion of linked tokens

    - Two tokens are linked if there is no space between them,
      e.g. `-` and `>` are linked in `->`, but not in `- >`

- Replaced `word` with `token` in the following options for consistency

    - `--max-word-search-dist`
    - `--index-chunk-word-count`

- Replaced `word` with `token` in user-facing text