add underline dash

Author: skjerns

README.rst

@@ -107,7 +107,7 @@ Additionally functionality as anonymizing, dropping or renaming channels can be
     highlevel.rename_channels('file.edf', mapping={'C3-M1':'C3'})
 
 Citation
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+--------
 
 If you use our software as part of a scientific publication, please cite us. Releases can be cited via Zenodo.