docs: API docstrings cleanup for better documentation rendering (#3661)

# What does this PR do?
* Cleans up API docstrings for better documentation rendering

<img width="2346" height="1126" alt="image"
src="https://github.com/user-attachments/assets/516b09a1-2d5b-4614-a3a9-13431fc21fc1"
/>

## Test Plan
* Manual testing

---------

Signed-off-by: Doug Edgar <dedgar@redhat.com>
Signed-off-by: Charlie Doern <cdoern@redhat.com>
Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>
Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: ehhuang <ehhuang@users.noreply.github.com>
Co-authored-by: Ashwin Bharambe <ashwin.bharambe@gmail.com>
Co-authored-by: Matthew Farrellee <matt@cs.wisc.edu>
Co-authored-by: Doug Edgar <dedgar@redhat.com>
Co-authored-by: Christian Zaccaria <73656840+ChristianZaccaria@users.noreply.github.com>
Co-authored-by: Anastas Stoyanovsky <contact@anastas.eu>
Co-authored-by: Charlie Doern <cdoern@redhat.com>
Co-authored-by: Francisco Arceo <arceofrancisco@gmail.com>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Young Han <110819238+seyeong-han@users.noreply.github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

docs/docs/providers/files/index.mdx

@@ -1,4 +1,7 @@
 ---
+description: "Files
+
+    This API is used to upload documents that can be used with other Llama Stack APIs."
 sidebar_label: Files
 title: Files
 ---
@@ -7,4 +10,8 @@ title: Files
 
 ## Overview
 
+Files
+
+    This API is used to upload documents that can be used with other Llama Stack APIs.
+
 This section contains documentation for all available providers for the **files** API.

docs/docs/providers/inference/index.mdx

@@ -1,5 +1,7 @@
 ---
-description: "Llama Stack Inference API for generating completions, chat completions, and embeddings.
+description: "Inference
+
+    Llama Stack Inference API for generating completions, chat completions, and embeddings.
 
     This API provides the raw interface to the underlying models. Two kinds of models are supported:
     - LLM models: these models generate \"raw\" and \"chat\" (conversational) completions.
@@ -12,7 +14,9 @@ title: Inference
 
 ## Overview
 
-Llama Stack Inference API for generating completions, chat completions, and embeddings.
+Inference
+
+    Llama Stack Inference API for generating completions, chat completions, and embeddings.
 
     This API provides the raw interface to the underlying models. Two kinds of models are supported:
     - LLM models: these models generate "raw" and "chat" (conversational) completions.

docs/docs/providers/safety/index.mdx

@@ -1,4 +1,7 @@
 ---
+description: "Safety
+
+    OpenAI-compatible Moderations API."
 sidebar_label: Safety
 title: Safety
 ---
@@ -7,4 +10,8 @@ title: Safety
 
 ## Overview
 
+Safety
+
+    OpenAI-compatible Moderations API.
+
 This section contains documentation for all available providers for the **safety** API.