message: Improve selection expansion changelog entry
diff: @@ -29,7 +29,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
  - Support for Fontconfig embolden and matrix options
  - Opt-out compilation flag `winpty` to disable WinPTY support
  - Scrolling during selection when mouse is at top/bottom of window
  -- Expanding existing selections using the right mouse button
  +- Expanding existing selections using single, double and triple click with the right mouse button
  - Support for `gopher` and `gemini` URLs
  - Unicode 13 support
  - Option to run command on bell which can be set in `bell.command`
  