Retext

* Dependency changes:
- Python 3.9 or later is now required.
- Markups 4.0 or later is now required.
* Improvements and bugs fixed:
- Issue 622 — added support for Ctrl+Tab and Ctrl+Shift+Tab for switching
tabs.
- PR 634 — WebEngine previewer now shows link on hover (contributed by
red-kite).
- Issue 623, PR 640 — changed mouse cursor to pointing hand on link
hover (contributed by Donjan Rodic).
- Added F9 shortcut for showing/hiding directory tree dynamically.
- In the directory tree, for files with long names the full name is shown
in a tooltip.
- Issue 383 — splitter state and WebEngine preview zoom factor are now
cached between runs.
- Preferences dialog now has links to open the selected stylesheet file
and working directories externally.
- It is now possible to pass a directory on the command line, it will be
shown in the tree.
- Issue 649 — pasted image URLs are now converted to image markup.
- Issue 650 — pressing Up key on the first line moves the cursor to the
beginning of the document, and pressing Down key on the last line moves
it to the end of the document.
- When the system theme is dark, Qt WebEngine now uses dark mode too.
- Issue 617 — added `markdownHeaders` setting for the highlighter.
- Issue 489 — added initial AsciiDoc support (beta).
- Issue 519 — added Ctrl+H shortcut for viewing HTML code.
* Internal changes:
- PR 592 — auto-generated config options were moved to a separate file,
`cache.conf` (contributed by Okko Makkonen).
- Build system was ported to `pyproject.toml`.
- Adopted `ruff` for code quality checks.
* Translation updates:
- Danish (contributed by Morten Juhl-Johansen).
- Dutch (contributed by Heimen Stoffels).
- Irish (new, contributed by Aindriú Mac Giolla Eoin).
- Italian (contributed by albanobattistella).
- Ukrainian (contributed by dmytro22).

* Improvements and bugs fixed:
- Fixed synchronized scrolling for zoom factors other than 1 (contributed
by Maurice van der Pot).
- Stopped passing `.desktop` suffix to setDesktopFileName() (contributed
by Chris Mayo in 633).
- Issue 98 — Made `mdx_posmap` not break indented code blocks which use
`pymdownx.superfences` extension.
- Issue 637 — Fixed crash when clicking on line information area.
* Translations updated:
- Basque (contributed by Aitor Salaberria).
- German (contributed by cosmic_snow).
- Korean (contributed by Minpa Lee).
- Ukrainian (contributed by Oleksandr Tsvirkun).

* Bugs fixed:
- Issue 594 — Fix opening files in existing window by relative path.
- Issue 597 — Fix unreachable text at the bottom of the file.
- Issue 599 — Fix truncating file when new text cannot be encoded with
the selected encoding.
- Issue 604 — Allow WebEngine renderer to load iframes such as YouTube
embeds.
- Issue 609 — Fix incorrect font size with WebEngine renderer.
- Issue 620 — LICENSE_GPL file now has text of GPL v2.
* Translations updated:
- Dutch (contributed by Heimen Stoffels).
- French (contributed by uGwA0XP3cm2w).
- Italian (contributed by Alessandro Melillo).
- Norwegian (Bokmål) (new, contributed by Sverre Våbenø).
- Persian (contributed by Hadi F and Arya Younesi).
- Portuguese (Brazil) (contributed by Rodrigo Zimmermann).
- Spanish (contributed by Antonio Villamarin).
- Turkish (contributed by Serkan ÖNDER).

* Dependency changes:
- ReText is now using Qt 6 and PyQt6.
- PyQt6-WebEngine is required for JavaScript support.
- WebKit is no longer supported.
* Improvements and bugs fixed:
- PR 543 — Added Apply button to Preferences dialog (contributed by Amos
Kong).
- Issue 384 — Save button is now enabled in auto-save mode.
- Issue 536 — Support spell checking for multiple languages.
- Issue 555 — Support setting bold font for editor.
- Issue 581 — Added backtick key to surround keys.
- Run-time resources are now installed into package directory.
- `setup.py` now allows building wheels.
* Translations updated:
- Polish (contributed by Maciej Haudek).
- Spanish (contributed by Pedro Torcatt).
- Turkish (contributed by Serkan ÖNDER in 556).

* Issues 573, 574 — Fixed TypeError crash with Python 3.10 and Qt WebKit.
* Translations updated:
- Chinese (China) (contributed by liulitchi).
- Portuguese (Brazil) (contributed by Igor Garcia and Christiano Morais).
- Slovak (contributed by Jose Riha).

* Issue 552 — Fixed bad Spanish translation causing a crash.
* Fixed `TypeError: index 0 has type 'float' but 'int' is expected` with
Python 3.10.
* Fixed `RuntimeError: ffi_prep_cif_var failed` in XSettings code.