[theme] inspect tool for workbench colors

Issue Type: Feature Request Relevant Issues: There was one but I'm unable to find it, this is an idea to perhaps explore it. Maybe the bot can find it. ## Live Editor Theming The original issue puts forward the idea of live editing a theme, such that when a change is applied, it's applied automatically without reloads and allows the developee to see what exactly changed. There are still a few downsides that I feel this feature request would solve. But before I explain, I'll describe my idea to push it further. ## Idea In-depth My plan is to perhaps be able to have a 'Theme Dev Mode' of some sorts where the editor is put into a 'frozen' state (by this, I don't mean a 'Not Responding' state, but rather you can't type, UI actions don't do anything but are toggleable, basically a disabled state) and devs are able to click on various UI elements or scopes to open a pop up detailing all the possible relevant scopes that can be defined. This is similar to the current `Developer: Inspect TM Scopes` but adds in support for UI too, and would be part of the 'live' experience ## How would this benefit developers The original issue stated that it would help theme developers (the live theme idea in general), and I believe this notion. would. boost the efficiency further. Currently many devs probably go to the docs to find their relevant UI scope, but this could be made easier as the pop ups detailed here could also be powered by docs. ## Issues this specific idea would solve (relating to this idea, not necessarily the original issue) - Time consumed searching for scopes - Much more friendly towards new devs Cons: - May be hard to implement, though the 'disabled' state is one thatvs started groundwork in the Walkthrough on the Welcome page