[Graph] Different styling for Custom Errors

[tintinweb]

copy pasting from: Consensys/vscode-solidity-auditor#101
original author: @C-Mierez

---

Greetings.

This is a bit of niche suggestion perhaps, but I noticed when generating a graph on a contract that has Custom Errors defined, these are graphed the same way as regular functions.

For example, given this contract:

The generated graph is:

I like the idea of having errors showing in the graph, but it would be nice if they had some different styling to tell them apart from actual contract functions.

And as a side-note, it's interesting that events are not included at all. Perhaps that's something that could be looked into as well.

[GNSPS]

Fixed it by adding a new flag to the command and changing the design of error nodes! 😊