Add editor setting for spin slider sensibility

[winston-yallow]

This PR adds an editor setting "Float Drag Speed" to control the base speed of dragging EditorSpinSlider nodes. It is applied directly to grabbing_spinner_dist_cache which means that all the other logic (pressing shift to slow down; pressing control to snap to integers; and always being a multiple of step) works flawlessly with the new speed. The initial value for the setting is 5.0 to increase the base speed.

Closes godotengine/godot-proposals/issues/3017
Probably also makes godotengine/godot-proposals/issues/2760 obsolete. That proposal requests a key to increase the drag speed. With this PR it would instead have an increased base speed, using the existing shift modifier to slow the speed down if needed. This is in line with other applications like blender that use a similar approach.

[Calinou]

I think the setting should influence the speed of dragging both floating-point and integer values.

[winston-yallow]

it does already influence the integer values, as those are calculated based on this floating point value
https://github.com/godotengine/godot/blob/5993060f49dd7e97e044deb87760d3b743ad00be/editor/editor_spin_slider.cpp#L127

[fire]

Needs an update.

[winston-yallow]

Rebased on current master and adjusted to use EDITOR_SETTING macro like all other settings in master. Therefore this cannot be easily cherry-picked for 3.x anymore. Should I make a second PR for 3.x once this is accepted?

Also I wasn't really able to test this in 4.x as dragging does not work for me (neither with or without this PR).

[winston-yallow]

Updated to work with current master. From my side this is ready now.

[winston-yallow]

And now the CI should be happy too 🤞

[akien-mga]

It crashes when generating the documentation, instantiating EditorSpinSlider while probably EditorSettings doesn't exist as a singleton. From the CI logs:

 editor/gui/editor_spin_slider.cpp:709:63: runtime error: member access within null pointer of type 'struct EditorSettings'
core/object/object.cpp:311:6: runtime error: member access within null pointer of type 'const struct Object'

================================================================
handle_crash: Program crashed with signal 11
Engine version: Godot Engine v4.1.dev.custom_build (67caeac3de2cb07e1907fbac65cb4e99d19a8914)
Dumping the backtrace. Please include this when reporting the bug to the project developer.
[1] ./bin/godot.linuxbsd.editor.dev.double.x86_64.san(+0x3ae94384) [0x55b998cc9384] (??:?)
[2] /lib/x86_64-linux-gnu/libc.so.6(+0x43090) [0x7f91b19f2090] (??:0)
[3] Object::get(StringName const&, bool*) const (??:?)
[4] EditorSpinSlider::EditorSpinSlider() (??:?)
[5] Object* ClassDB::creator<EditorSpinSlider>() (??:?)
[6] ClassDB::instantiate(StringName const&) (??:?)
[7] ClassDB::class_get_default_property_value(StringName const&, StringName const&, bool*) (??:?)
[8] ./bin/godot.linuxbsd.editor.dev.double.x86_64.san(+0x44e43d37) [0x55b9a2c78d37] (??:?)
[9] DocTools::generate(bool) (??:?)
[10] EditorHelp::generate_doc(bool) (??:?)
[11] EditorNode::EditorNode() (??:?)
[12] Main::start() (??:?)
[13] ./bin/godot.linuxbsd.editor.dev.double.x86_64.san(main+0x3da) [0x55b998cc8a83] (??:?)
[14] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf3) [0x7f91b19d3083] (??:0)
[15] ./bin/godot.linuxbsd.editor.dev.double.x86_64.san(_start+0x2e) [0x55b998cc85ee] (??:?)
-- END OF BACKTRACE --
================================================================

[akien-mga]

Thanks!