Fix Formatting in aixacct.read_tfdata docstring

[JAnderson419]

Docstring for read_tfdata has poor formatting in docs. Relevant portion below

https://ferro.readthedocs.io/en/latest/aixacct.html

Returns data in a dictionary of following structure :
filename:
'meastype': MeasEnum.HYSTERESIS,
'datatables':
'Table #':
'metadata':
Waveform: triangle
SampleName: RTWhiteB
Area [mm2]: 0.01
Thickness [nm]: 255
...
'data':
'0.000000e+000\t3.235215e-004\t ...'