Increase ItemList item height in editor theme

[fire-forge]

Makes ItemList use the same item height as PopupMenu. This makes it easier to select items.

With the default theme, items are only 2 pixels taller, so there is not a huge difference but it still goes a long way in making it easier to select ItemList items and making the UI look less squished together.

Before	After

[Mickeon]

I like the "extra squashing" in the File System but I do understand the decision.

[YuriSizov]

I'm fine with this change, but it kind of sucks that this is the minimum and people who'd preferred a more squashed look cannot do anything about it.

Both before and after this change the property is controlled by the additional spacing editor setting, so technically if you want the UI to be more spacious, you can achieve that (but it will affect a whole lot of other things too). But personally, I'd prefer this to be what users see out of the box. And it matches popup menus.

[Calinou]

Currently, ItemList in the editor theme uses a 26 pixel-tall highlight, while this PR uses 28 a pixel-tall highlight. (By the way, there's an off-by-one error in the Y offset of the selection highlight drawing.)

For reference, this is the line spacing I use in Dolphin (KDE's file manager) in details mode. This is the second lowest zoom level (highlight is 26 pixels tall, like before this PR):

I find Dolphin's spacing a tad too low in some cases, so I think this PR is a good change.

As for spacing on small displays, we can allow the Additional Spacing editor setting to have a negative value in a separate PR (up to -3 or so).

[YuriSizov]

Thanks!

[fire-forge]

it kind of sucks that this is the minimum and people who'd preferred a more squashed look cannot do anything about it.

Both before and after this change the property is controlled by the additional spacing editor setting, so technically if you want the UI to be more spacious, you can achieve that (but it will affect a whole lot of other things too).

I've seen many people saying that the editor UI has too much padding on proposals and discussions. To fix that, I think the additional spacing setting of 0 should be made more compact than it is now, and the default value should be changed to something like 2. 2 would look the same as what we have now, and 0 would look something like Blender's UI, which has a lot less space than Godot.

Those who want a more compact editor could change additional spacing to 0 or 1.

It would take a lot of work to adjust the editor theme for all node types though, so I think the change done here is good because it makes ItemList and PopupMenu consistent.

[Mickeon]

I know it's no place for discussion but with the current padding all around even testing Godot 4 on a screen laptop is... quite the task. Certainly it can be mitigated by shrinking the view to 75%, but it's not exactly a great first impression.

[fire-forge]

I know it's no place for discussion but with the current padding all around even testing Godot 4 on a screen laptop is... quite the task. Certainly it can be mitigated by shrinking the view to 75%, but it's not exactly a great first impression.

I agree that it should be possible to use the editor with less padding. I like the current amount of padding on my 1920x1280 screen, but I know many users have smaller screens or just prefer a more compact view.