docs: drop hardcoded database list from mcpb page

"All supported databases" doesn't go stale when a new connector lands.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: tianzhou

docs/mcpb.mdx

@@ -11,7 +11,7 @@ The [MCP Bundle](https://github.com/modelcontextprotocol/mcpb) (`.mcpb`) is a on
 2. Install it in your client — in Claude Desktop, double-click the file (or drag it into **Settings → Extensions**).
 3. Enter your database connection string when prompted, e.g. `postgres://user:password@host:5432/dbname`. It is stored in the OS keychain, not in a config file.
 
-The bundle includes drivers for PostgreSQL, MySQL, MariaDB, SQL Server, and SQLite, and runs locally over stdio.
+The bundle includes the drivers for all supported databases and runs locally over stdio.
 
 ### Clients without native .mcpb support