Rephrase the "what it solves" part of the Durable Objects landing page.

Parts of this felt redundant with the newly-added section below. Also, I wanted to work in a mention of deeper distributed systems. Durable Objects are not just about collaborative apps.

Author: kentonv

src/content/docs/durable-objects/index.mdx

@@ -19,9 +19,9 @@ Create collaborative applications, real-time chat, multiplayer games and more wi
 
 <Plan type="paid" />
 
-Durable Objects provide a powerful compute API for coordinating multiple clients or users. Each Durable Object has private, transactional and strongly consistent storage attached.
+Durable Objects provide a building block for stateful applications and distributed systems.
 
-Use Durable Objects to build collaborative editing tools, interactive chat, multiplayer games and applications that need coordination among multiple clients, without requiring you to build serialization and coordination primitives on your own.
+Use Durable Objects to build applications that need cordination among multiple clients, like collaborative editing tools, interactive chat, multiplayer games, and deep distributed systems, without requiring you to build serialization and coordination primitives on your own.
 
 ### What is a Durable Object?