chore(deps): bump ratatui to 0.26.1

[orhun]

Also updated imports and simplified the dependency definition in Cargo.toml 🐻

[orhun]

Looks like there are some layout changes:

--- STDERR:              heh::bin/heh screen::tests::test_calculate_dimensions_no_popup ---
thread 'screen::tests::test_calculate_dimensions_no_popup' panicked at src/screen.rs:495:9:
assertion `left == right` failed
  left: 22
 right: 24
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Is that an issue? Should I just update the test?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 20.7%. Comparing base (c77f399) to head (3917ec1).

Additional details and impacted files

Files	Coverage Δ
src/character.rs	50.0% <ø> (+2.3%)	⬆️
src/screen.rs	21.9% <100.0%> (-0.3%)	⬇️
src/windows/jump_to_byte.rs	0.0% <ø> (ø)
src/windows/mod.rs	8.1% <ø> (+0.4%)	⬆️
src/windows/search.rs	47.1% <ø> (-0.5%)	⬇️
src/windows/unsaved_changes.rs	0.0% <ø> (ø)

... and 5 files with indirect coverage changes

[ndd7xv]

I tested and it seems like the Rect dimensions were slightly different, so the last character of each line was not being shown in the ASCII portion of the screen; I just changed that and I'm gonna merge this! Thanks!