[docs] clarify the mapping between `Transformer2DModel` and finegrained variants. (#11947)
* clarify the mapping between Transformer2DModel and finegrained variants.
* Update src/diffusers/pipelines/dit/pipeline_dit.py
Co-authored-by: Steven Liu <59462357+stevhliu@users.noreply.github.com>
* fix
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Co-authored-by: Steven Liu <59462357+stevhliu@users.noreply.github.com>