Remove em dash causing codec error on some systems

doped/VASP_sets/DefectSet.yaml

@@ -9,7 +9,7 @@ INCAR:
 # Notes:
 # KPAR is set to 2 for `vasp_std` calculations (multiple kpoints)
 # NUPDOWN is set to 0 (singlet) or 1 (doublet) depending on the number of electrons
-# (even or odd, respectively) – see https://doped.readthedocs.io/en/latest/Tips.html#spin-polarisation
+# (even or odd, respectively) -- see https://doped.readthedocs.io/en/latest/Tips.html#spin-polarisation
 # Note that even-electron defects with multiple spin-polarised states (e.g. bipolarons;
 # Fig. 2c in doi.org/10.1021/acsenergylett.1c00380) could also have triplet spin states
 # (NUPDOWN=2), but the energy difference is likely to be small.