NEWS: Isabelle/jEdit dark mode

[Makarius]

*** Isabelle/jEdit Prover IDE ***

* Additional look-and-feels "FlatLaf macOS Light" and "FlatLaf macOS
Dark" imitate original macOS more closely. This is the default for the
bundled application on macOS.

* GUI rendering for dark look-and-feels has been slightly improved:
colors and icons, notably the menu accelerator font/color.

* Explicit support for dark GUI themes: FlatLaf tells wether a Swing
look & feel is dark or non-dark (default); jEdit options with suffix
".dark" and Isabelle options with suffix "_dark" determine GUI rendering
in dark mode. The panels for "Global Options" and "Plugin Options /
Isabelle / Rendering" operate on options according to the current Swing
look & feel, e.g. on "view.fgColor.dark" in dark mode vs. "view.fgColor"
in non-dark mode.


This refers to Isabelle/f7007ebfb556. It is based on a bachelor project by Kai 
Naumann (supervised by Balazs Toth), LMU München. As often, I ended up 
changing the initial design and implementation in several rounds.

Side-remark: The place to change the jEdit look and feel is "Global Options / 
Appearance / Swing look & feel".


	Makarius