docs(block-kit): align carousel description to docs and simplify example doc

- README: use the docs carousel-block description ("Displays related card
  blocks in a horizontally-scrolling container.") to match the docstring
  first line.
- carousel.py: simplify the specific-example line to "A sample carousel
  block." (docs description first line + URL kept per AGENTS.md).

Co-Authored-By: Claude <svc-devxp-claude@slack-corp.com>

Author: zimeg

block-kit/README.md

@@ -11,7 +11,7 @@ Read the [docs](https://docs.slack.dev/block-kit/) to learn concepts behind thes
 - **[Actions](https://docs.slack.dev/reference/block-kit/blocks/actions-block)**: Holds multiple interactive elements. [Implementation](./src/blocks/actions.py).
 - **[Alert](https://docs.slack.dev/reference/block-kit/blocks/alert-block)**: Displays alerts, warnings, and informational messages. [Implementation](./src/blocks/alert.py).
 - **[Card](https://docs.slack.dev/reference/block-kit/blocks/card-block)**: Displays content in a card. [Implementation](./src/blocks/card.py).
-- **[Carousel](https://docs.slack.dev/reference/block-kit/blocks/carousel-block)**: Displays a scrollable, horizontal collection of cards. [Implementation](./src/blocks/carousel.py).
+- **[Carousel](https://docs.slack.dev/reference/block-kit/blocks/carousel-block)**: Displays related card blocks in a horizontally-scrolling container. [Implementation](./src/blocks/carousel.py).
 - **[Context](https://docs.slack.dev/reference/block-kit/blocks/context-block)**: Provides contextual info, which can include both images and text. [Implementation](./src/blocks/context.py).
 - **[Context actions](https://docs.slack.dev/reference/block-kit/blocks/context-actions-block)**: Displays actions as contextual info, which can include both feedback buttons and icon buttons. [Implementation](./src/blocks/context_actions.py).
 - **[Divider](https://docs.slack.dev/reference/block-kit/blocks/divider-block)**: Visually separates pieces of info inside of a message. [Implementation](./src/blocks/divider.py).

block-kit/src/blocks/carousel.py

@@ -8,8 +8,7 @@ def example01() -> CarouselBlock:
     Displays related card blocks in a horizontally-scrolling container.
     https://docs.slack.dev/reference/block-kit/blocks/carousel-block/
 
-    A carousel with three cards, each with an icon, title, subtitle, hero
-    image, body, and an action button.
+    A sample carousel block.
     """
     block = CarouselBlock(
         elements=[