Add table of contents to Gui/journal

[wiktor-obrebski]

Description

Add table of contents and undo/redo features to the gui/journal script.
Notable features:

• adding line starting from # give 1-th level ToC header. ## and more give more indented ToC links
• Ctrl+O toggle ToC
• visible "Shifter" button to show/hide ToC
• ToC panel can be resized by mouse
• click in ToC entry scroll to given header in the text
• CTRL+Z undo, CTRL+Y redo

Bugfixes:

• 2846 numbers are not longer interpreted as cursor moves

TODO later

• add buttons to insert new header of 1/2/3 indentation (to ToC panel?)
• stop render text on resize, it is slow
• consider hiding ToC panel (now panel without STYLE_FRAME can not be resized)

[myk002]

Copying here from Discord:

You can give it a frame style that renders gui.CLEAR_PEN like this:

local INVISIBLE_FRAME = {
    frame_pen=gui.CLEAR_PEN,
    signature_pen=false,
}

Also, there should be hotkeys to jump to prev/next heading for the keyboard-only users

Hotkey buttons could be added to the bottom, underneath a horizontal widgets.Divider, until we get icons for them, at which time they can be moved to the top

The vertical widgets.Divider for the ToC can link into the bottom horizontal Divider if you use the same frame_style (gui.FRAME_THIN)

[myk002]

this is awesome ; )

[wiktor-obrebski]

@myk002 there is a problem with A_MOVE_N_DOWN and other new test keys.
I added them, as we discussed, to control sections, but tests run on game version without beta yet (if I understand correctly), so the keys are not supported. So, in tests I get

error: ./hack/lua/gui.lua:65: Invalid keycode: A_MOVE_N_DOWN

And similar errors

[myk002]

Notes from playtesting:

The initial empty screen looks stark and scary. I think we need to add some help text:

1. In the main text area, add a short intro about what the tool is, and direct the player's attention to the ? button for further info. This text disappears as soon as there is user text
2. In the ToC area, show information about how to add headers. This text disappears once there is a header to show

The help blurbs can be implemented as additional widgets.WrappedLabel widgets that overlap the regular text areas and whose visible properties are set to functions that detect when they should be shown.

Possible main area help text:

Welcome to gui/journal! You can use this tool to take notes, track progress on your plans,
or anything else! The text you write here is saved with your fort. Please click on the ? button
in the upper right corner to see more information, including a list of keyboard navigation
hotkeys.

Possible ToC help text:

Start a line with # symbols to create headers. Those headers will appear here, and you can
click on them to jump to them in the text. Click on the ? button in the upper right corner
for more details.

[myk002]

merged so people can start testing a bit. We can figure out the help text in a different PR