Hey, great project and I love this concept of generating (metadata for) diagrams that document the codebase.

Using OperationWalker instead of CSharpSyntaxWalker will be more efficient for this project

• Better productivity when writing new analyzers as you the IOperation provides access to type metadata and more
• It will support VB as well, not only C#
• We'll have more context when writing these analyzers (ex: object obj = new(); currently doesn't work since it's an ImplicitObjectCreationExpressionSyntax and not an ObjectCreationExpressionSyntax) and we'll be able to provide more context (constant values and such)

This change doesn't look like a breaking change for the library since the constructor for SourceAnalyzer will not need to change at all.