Remove text to image tag

WebUIs build on top of diffusers start to rely on the HF Hub client library to filter for models. This one should not be displayed when listing "text-to-image" models:
```py
import huggingface_hub as hf
hf_api = hf.HfApi()
model_filter = hf.ModelFilter(
model_name="",
task='text-to-image',
tags='stable-diffusion',
library=['diffusers', 'stable-diffusion'],
)
res = hf_api.list_models(filter=model_filter, full=True, limit=200, sort="downloads", direction=-1)
```

README.md

@@ -2,7 +2,6 @@
 license: openrail++
 tags:
 - stable-diffusion
-- text-to-image
 inference: false
 ---