Re-think History Screen UI/UX

[lolloz98]

I think it would be nice to show all keybindings like in other screens.

Also I think History should be a modalScreen (it should not have the keybindings of underlying screen)

If this change is not wanted we can close the issue, but I have prepared a pr for this, so check it out :)

[tconbeer]

This issue describes a solution, not a problem. I think the problem is that the interactivity of the preview pane in the history screen makes for a confusing UI.

[lolloz98]

It seems that preventing focus on the TextEditor is simple to do, but via using the disabled parameter (which change the color scheme, so not sure if we want that). can_focus attribute seems to block navigation with keyboard but allows focus via mouse, so also meh

[tconbeer]

New read-only and hide-cursor methods will help: Textualize/textual#5934

Although there is also a new textual.highlights module to do syntax highlighting on other Content; so could probably replace the textarea with a Static that is highlighted (like the old days).