Auto (re)build project when C# script changes

[MaaaxiKing]

Describe the project you are working on

Old game where I rewrite GDScript code in C#

Describe the problem or limitation you are having in your project

I always must rebuild my project after declaring an export variable in my Script and that's not obvious, I agonized my brain over this!

Describe the feature / enhancement and how it helps to overcome the problem or limitation

Godot would rebuild the project everytime when a C# script changes, that means only after saving and if possible, only when the current version is not equal to the previous.

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

It's not visual.

If this enhancement will not be used often, can it be worked around with a few lines of script?

No

Is there a reason why this should be core and not an add-on in the asset library?

Yes, an add-on is too much effort for this basic thing.

[Calinou]

This requires implementing #849 and ideally #2231 first.