Consistently use "S2I2-HEP" rather than "S2I2/HEP"
Consistently use "S2I2-HEP" rather than "S2I2/HEP"

s2i2-hep/s2i2-hep.github.io-source,s2i2-hep/s2i2-hep.github.io-source,s2i2-hep/s2i2-hep.github.io-source