Undefining a function should remove associated symbol

[yrp604]

I have a bndb with some code I'm trying to understand. As part of this process, I'm moving a function boundary between two chunks of code. For example, if I have:

0x1000: func_a
...
0x2000: func_b

If I want to move func_b to start at 0x1800, my workflow is to create a new function at 0x1800, undefine func_b, then rename sub_1800 to func_b. This mostly works, except it sometimes leaves the old symbol for func_b, (especially if I've modified the argument list/type?) in my bv.symbols. If I'm moving function boundaries around a lot, these can build up and be annoying.

As a workaround, they can be manually deleted with bv.undefine_user_symbol(bv.symbols['sym_name']), but they should probably be deleted automatically with function undefine?

[galenbwill]

I've implemented this as a change to both API and core, as well as UI (with a setting to toggle it, defaulting to off).

For now, I'm leaving it on a test branch test_remove_user_symbols_with_functions, and I'll submit a PR for it.

Since it affects the C API, it needs further review.

[fuzyll]

We decided to reject the PR on this for the API because we didn't want to complicate things. But, we still feel this is important to do through the UI, so we're keeping this ticket open to track that.