DOC: clarify docstring for stc object (#6971)
DOC: clarify docstring for stc object (#6971)

* DOC: clarify docstring for stc object

* FIX indentation as suggested by @drammock

* Add space

* DOC: change everywhere data and vertices

* Address comments by Alex

* List of array consistently

* List of array?

* FIX for vector source estimate

* Address comments

* DOC update mixed source space

mne-tools/mne-python,mne-tools/mne-python,larsoner/mne-python,Eric89GXL/mne-python,olafhauk/mne-python,Teekuningas/mne-python,Teekuningas/mne-python,wmvanvliet/mne-python,drammock/mne-python,rkmaddox/mne-python,bloyl/mne-python,wmvanvliet/mne-python,olafhauk/mne-python,cjayb/mne-python,larsoner/mne-python,wmvanvliet/mne-python,bloyl/mne-python,kambysese/mne-python,Eric89GXL/mne-python,pravsripad/mne-python,drammock/mne-python,larsoner/mne-python,pravsripad/mne-python,kingjr/mne-python,kambysese/mne-python,kingjr/mne-python,olafhauk/mne-python,pravsripad/mne-python,rkmaddox/mne-python,cjayb/mne-python,drammock/mne-python,kingjr/mne-python,mne-tools/mne-python,Teekuningas/mne-python