Description of the Issue

Cython files (.pyx, .pxd and .pxi) are not recognized by npp. The Cython keywords are
actually Python keywords + couple specific ones (cdef, cpdef) and also C types of data
should be highlighted too. I think that scintilla Python lexer supports Cython.

Steps to Reproduce the Issue

1. Open any Cython file (rename python file *.py to *.pyx)
2. NPP says it is a Normal text file
3. Keyword are not highlighted, etc.

Expected Behavior

Actual Behavior

npp is not recognizing cython files.

Debug Information

None.

https://cython.readthedocs.io/en/latest/src/reference/language_basics.html