[Docs] fixed some typos (open-mmlab#1425)

fixed typos

docs/source/api/pipelines/alt_diffusion.mdx

@@ -51,7 +51,7 @@ To use a different scheduler, you can either change it via the [`ConfigMixin.fro
 ```
 
 
-- *How to conver all use cases with multiple or single pipeline*
+- *How to convert all use cases with multiple or single pipeline*
 
 If you want to use all possible use cases in a single `DiffusionPipeline` we recommend using the `components` functionality to instantiate all components in the most memory-efficient way:
 

docs/source/api/pipelines/stable_diffusion.mdx

@@ -48,7 +48,7 @@ To use a different scheduler, you can either change it via the [`ConfigMixin.fro
 ```
 
 
-### How to conver all use cases with multiple or single pipeline
+### How to convert all use cases with multiple or single pipeline
 
 If you want to use all possible use cases in a single `DiffusionPipeline` you can either:
 - Make use of the [Stable Diffusion Mega Pipeline](https://github.com/huggingface/diffusers/tree/main/examples/community#stable-diffusion-mega) or 

docs/source/api/pipelines/stable_diffusion_2.mdx

@@ -22,7 +22,7 @@ For more details about how Stable Diffusion 2 works and how it differs from Stab
 
 ## Tips
 
-### Avaiblable checkpoints:
+### Available checkpoints:
 
 Note that the architecture is more or less identical to [Stable Diffusion 1](./api/pipelines/stable_diffusion) so please refer to [this page](./api/pipelines/stable_diffusion) for API documentation.