Provide a "declaration" icon overlay

[elahehrashedi]

For C/C++ extension, we would like a "declaration" icon overlay.

the related vscode issue: #23927
here is the cpptools related issue we want to address: microsoft/vscode-cpptools#3117

The result our C/C++ extension wants is just the ability to have our completion/symbol icons match VS:
Completion has a max of 1 modifier:

Symbols has a max of 2 modifiers:

Looking at C#, they have an additional "internal" icon modifier too (the "protected internal" and "private protected" cases are not given unique icons). Only 1 modifier max.

From a UI design/implementation perspective, it seems like the max icon modifiers would be around 3, with the base icon image rendered in the top left (bigger than the modifiers), and potential modifiers rendered on the bottom left, bottom right, and top right. Unless modifiers could change rendering of the base icon in other ways, such as color modulation or a transparent overlay over the entire base icon (e.g. "strikeout").

[jrieken]

/duplicate of #23927

Close this as dupe because #23927 is about the design and candidates for overlay. Please add a comment there with what "modifier" you need

[elahehrashedi]

@jrieken The conversation on the #23927 issue is locked and limited to collaborators. Would you please unlock it?

[jrieken]

Oh, sorry. I got that wrong..

[sean-mcmanus]

The original bug report images have some errors. To summarize, with code

class foo
{
public:
	int publicFuncDefinition(){}
	int publicFuncDeclaration();
private:
	int privateFuncDefinition(){}
	int privateFuncDeclaration();
protected:
	int protectedFuncDefinitio(){}
	int protectedFuncDeclaration();
};

we want to be able to provide results like

[sean-mcmanus]

This is what our workaround looks like without icons: