[Docs] Fix scheduler docs (#421)

* [Docs] Fix scheduler docs

* up

* Apply suggestions from code review

docs/source/api/schedulers.mdx

@@ -14,7 +14,8 @@ specific language governing permissions and limitations under the License.
 
 Diffusers contains multiple pre-built schedule functions for the diffusion process.
 
-## What is a schduler?
+## What is a scheduler?
+
 The schedule functions, denoted *Schedulers* in the library take in the output of a trained model, a sample which the diffusion process is iterating on, and a timestep to return a denoised sample.
 
 - Schedulers define the methodology for iteratively adding noise to an image or for updating a sample based on model outputs.
@@ -23,73 +24,77 @@ The schedule functions, denoted *Schedulers* in the library take in the output o
 - Schedulers are often defined by a *noise schedule* and an *update rule* to solve the differential equation solution.
 
 ### Discrete versus continuous schedulers
+
 All schedulers take in a timestep to predict the updated version of the sample being diffused.
 The timesteps dictate where in the diffusion process the step is, where data is generated by iterating forward in time and inference is executed by propagating backwards through timesteps.
-Different algorithms use timesteps that both discrete (accepting `int` inputs), such as the [`DDPMScheduler`] or [`PNDMScheduler`], and continuous (accepting 'float` inputs), such as the score-based schedulers [`ScoreSdeVeScheduler`] or [`ScoreSdeVpScheduler`].
+Different algorithms use timesteps that both discrete (accepting `int` inputs), such as the [`DDPMScheduler`] or [`PNDMScheduler`], and continuous (accepting `float` inputs), such as the score-based schedulers [`ScoreSdeVeScheduler`] or [`ScoreSdeVpScheduler`].
 
 ## Designing Re-usable schedulers
+
 The core design principle between the schedule functions is to be model, system, and framework independent.
 This allows for rapid experimentation and cleaner abstractions in the code, where the model prediction is separated from the sample update.
 To this end, the design of schedulers is such that:
+
 - Schedulers can be used interchangeably between diffusion models in inference to find the preferred trade-off between speed and generation quality.
 - Schedulers are currently by default in PyTorch, but are designed to be framework independent (partial Numpy support currently exists).
 
 
 ## API
+
 The core API for any new scheduler must follow a limited structure.
 - Schedulers should provide one or more `def step(...)` functions that should be called to update the generated sample iteratively.
 - Schedulers should provide a `set_timesteps(...)` method that configures the parameters of a schedule function for a specific inference task.
 - Schedulers should be framework-agonstic, but provide a simple functionality to convert the scheduler into a specific framework, such as PyTorch
 with a `set_format(...)` method.
 
-### Core
 The base class [`SchedulerMixin`] implements low level utilities used by multiple schedulers.
 
-#### SchedulerMixin
+### SchedulerMixin
 [[autodoc]] SchedulerMixin
 
-#### SchedulerOutput
+### SchedulerOutput
 The class [`SchedulerOutput`] contains the ouputs from any schedulers `step(...)` call.
+
 [[autodoc]] schedulers.scheduling_utils.SchedulerOutput
 
-### Existing Schedulers
+### Implemented Schedulers
 
 #### Denoising diffusion implicit models (DDIM)
 
 Original paper can be found here.
 
-[[autodoc]] schedulers.scheduling_ddim.DDIMScheduler
+[[autodoc]] DDIMScheduler
 
 #### Denoising diffusion probabilistic models (DDPM)
 
 Original paper can be found [here](https://arxiv.org/abs/2010.02502).
 
-[[autodoc]] schedulers.scheduling_ddpm.DDPMScheduler
+[[autodoc]] DDPMScheduler
 
 #### Varience exploding, stochastic sampling from Karras et. al
 
 Original paper can be found [here](https://arxiv.org/abs/2006.11239).
 
-[[autodoc]] schedulers.scheduling_karras_ve.KarrasVeScheduler
+[[autodoc]] KarrasVeScheduler
 
 #### Linear multistep scheduler for discrete beta schedules
 
 Original implementation can be found [here](https://arxiv.org/abs/2206.00364).
 
 
-[[autodoc]] schedulers.scheduling_lms_discrete.LMSDiscreteScheduler
+[[autodoc]] LMSDiscreteScheduler
 
 #### Pseudo numerical methods for diffusion models (PNDM)
 
 Original implementation can be found [here](https://github.com/crowsonkb/k-diffusion/blob/481677d114f6ea445aa009cf5bd7a9cdee909e47/k_diffusion/sampling.py#L181).
 
-[[autodoc]] schedulers.scheduling_pndm.PNDMScheduler
+[[autodoc]] PNDMScheduler
 
 #### variance exploding stochastic differential equation (SDE) scheduler
 
 Original paper can be found [here](https://arxiv.org/abs/2011.13456).
 
-[[autodoc]] schedulers.scheduling_sde_ve.ScoreSdeVeScheduler
+[[autodoc]] ScoreSdeVeScheduler
 
 #### variance preserving stochastic differential equation (SDE) scheduler