add condition for get_acc

[fabianmoss]

https://github.com/DCMLab/pitchplots/blob/e4440dcb7236828d4790258fb81639ddaa3b2bdf/functions.py#L107

I am not sure anymore how we dealt with it but I have files with double sharps that are encoded as "x" and not "##". And I am quite sure I used the Magenta parser.

We could add:

if i == 'x':
    acc = acc + 2