[FIX] Correct manacc documentation and check for associated inputs

[tsalo]

Closes #753.

Changes proposed in this pull request:

• Describe mutually dependent parameters in argument parser and workflow docstring.
• Check that both ctab and mmix are provided if manacc is, rather than just checking for mmix.

[codecov]

Codecov Report

Merging #754 (6d5bdb1) into main (319bbba) will not change coverage.
The diff coverage is 50.00%.

@@           Coverage Diff           @@
##             main     #754   +/-   ##
=======================================
  Coverage   92.59%   92.59%           
=======================================
  Files          27       27           
  Lines        2121     2121           
=======================================
  Hits         1964     1964           
  Misses        157      157           

Impacted Files	Coverage Δ
tedana/workflows/tedana.py	90.30% <50.00%> (ø)

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[eurunuela]

LGTM!

[jbteves]

LGTM, thanks @tsalo ! I fiddled around with trying to make things required via argparse, but you don't get as informative of error messages. The only upside would be that the parser fails much faster than loading the images and then checking some of these args, so I think your implementation is a better trade-off!

[tsalo]

Thanks @jbteves and @eurunuela.

@jbteves, yeah that seems like an unfortunate gap in argparse.