Fix Cython tag generation for NumPy arrays

The Python package NumPy allows for typed arrays in Python. Those can by interfaced at C level using Cython. A typical declaration then looks like

cpdef numpy.ndarray[ndim=1, dtype=double] my_func(numpy.ndarray[ndim=2, dtype=complex] x)

So far, the equal sign in the ndarray declaration prevented ctags from generating tags. Functions with complex ndarray data types have been missing in the symbol list. This PR fixes and adds a test.