@Amxx I changed this to keep dummy variables for ErrorDefinition, FunctionDefinition, and VariableDeclaration, but avoids duplicate identifiers if one already exists due to overloading. For now I think FunctionDefinition is really the only case where overloading could occur, but it could happen for ErrorDefinition when Solidity eventually supports overloading custom errors. So for simplicity, I use the same code for all 3 of these cases.

We now also replace UsingForDirective with dummy enums to avoid orphaning their NatSpec. The NatSpec of UsingForDirective is not part of the AST so we cannot easily delete those.

Can you please review the overall changes?

Summary:

Changed to not delete any nodes and not delete documentation. Instead, replaces functions and other unneeded nodes with dummy enums, either with the original name (if the identifier could be imported in other files) or with a random identifier based on the AST node ID (if the identifier is no longer relevant or if it was originally an overloaded function).

This avoids any possibility of NatSpec getting orphaned or mixed up with different nodes than originally written, which could lead to compile errors. Enums are able to compile with any NatSpec tag even if they are not relevant.