BUR #60370 has been approved by @evazion.
create alias stereo_rotom -> dj_rotom
These are the same Pokémon. "DJ Rotom" is the name of the character, while "Stereo Rotom" is the name of the form. DJ Rotom is the only Stereo Rotom, so I don't see much of a reason to have tags for both. I guess there is the possibility that this form could appear in future games, but until that happens (if at all), these tags are basically interchangeable.
I chose stereo_rotom as the alias and dj_rotom as the main tag due to the former being used far less frequently. As far as I'm aware, the term "Stereo Rotom" only appears in the in-game Pokédex.