Change synthesis.py to numpydoc style

[KybernetikJo]

This PR refactors the Slycot/slycot/synthesis.py in order to be closer to the numpydoc style as discussed in #100. Should be part of #204.

Remark: The synthesis.py has already been quite close to numpydoc before this PR. There must have been major cleanups in the past.

(finished 18 of 18 = (17 + 1) routines)

Routine name	Finished	Status description
sb01bd	[x]	*3
sb02md	[x]	*3
sb02mt	[x]	*3
sb02od	[x]	*3
sb03md	[x]	*3
sb03md57	[x]	*3
sb03od	[x]	*3
sb04md	[x]	*3
sb04qd	[x]	*3
sb10ad	[x]	*3
sb10dd	[x]	*3
sb10fd	[x]	*3
sb10hd	[x]	*3
sb10jd	[x]	*3
sb10yd	[x]	*3
sg02ad	[x]	*3
sg03ad	[x]	*3
sg03bd	[x]	*3

Status description:

1. numpydoc docstring sections, fixed
2. parameters data types, fixed and 1 fixed
3. optional and default values, fixed and 2 fixed

[KybernetikJo]

The test coverage drops, because the routine sb10jd has been added to init.py, but there is no pytest for it.

[bnavigator]

The test coverage drops, because the routine sb10jd has been added to init.py, but there is no pytest for it.

It's actually because of the removal of the last :info = -i: from the docstrings:

The following block is not covered properly.

https://github.com/python-control/Slycot/blob/5b6587774fe51e51bdfbfb48285d797a6206a39b/slycot/exceptions.py#L104-L114

This is outside of the scope of this PR.

[bnavigator]

Thanks a lot @KybernetikJo!