[core] Remove flatten for Matmul?

What commit version of aidge do you use

• aidge_core: dev

Problem description

The remove_flatten recipe only works when the flatten is followed by a FC layer from what I see. Would it be possible to make it work for MatMul layers as well? Or is there something preventing this?

By the way, the API documentation for the C++ code does mentions Remove Flatten before :cpp:function:Aidge::FC Node. but the Python API documentation only says Recipie to remove a flatten operator. without mentioning the FC layer condition.