Regression: Reference indexing operator T& operator[](U index) is typed as void operator[](U index)

[Wizzerinus]

Originally found by researching types-panda3d built against my version of panda3d, which bases off 1.11.0. The, for example, LVecBase4f has the following code:

  INLINE_LINMATH FLOATTYPE operator [](int i) const;
  INLINE_LINMATH FLOATTYPE &operator [](int i);

and this is what igate gives:

wrapper.return_type=IDBType(index=137), wrapper.parameters=IDBFunctionWrapper.ParameterList(wrapper_index=5046), wrapper.comment='/**\n *\n */'
IDBFunctionWrapper(index=5046) (self, i: int) -> None
wrapper.return_type=IDBType(index=1742), wrapper.parameters=IDBFunctionWrapper.ParameterList(wrapper_index=5047), wrapper.comment=''
IDBFunctionWrapper(index=5047) (self, i: int) -> float

regression from 1.10.x, as types-panda3d properly builds on that version