Apply suggestions from code review

Co-authored-by: Sarah Rainsberger <[email protected]>

.changeset/ten-emus-heal.md

@@ -2,13 +2,16 @@
 'astro': minor
 ---
 
-Adds the `build.concurreny` to specify the number of pages to build in parallel. In most cases, you should stick with the default value of `1`,
-and batch or cache long running tasks like fetch calls or data access to improve the overall rendering time.
+Adds a new `build.concurreny` configuration option to specify the number of pages to build in parallel
 
-Use this option only if the refactors are not possible. If the number is set too high, the page rendering
-may slow down due to insufficient memory resources and because JS is single-threaded.
+**In most cases, you should not change the default value of `1`.**
 
-In the future, Astro may reuse this option to render pages concurrently with multiple threads.
+Use this option only when other attempts to reduce the overall rendering time (e.g. batch or cache long running tasks like fetch calls or data access) are not possible or are insufficient.
+
+Use this option only if the refactors are not possible. If the number is set too high, the page rendering may slow down due to insufficient memory resources and because JS is single-threaded.
+
+> [!WARNING]
+> This feature is stable and is not considered experimental. However, this feature is only intended to address difficult performance issues, and breaking changes may occur in a [minor release](https://docs.astro.build/en/upgrade-astro/#semantic-versioning) to keep this option as performant as possible.
 
 ```js
 // astro.config.mjs

packages/astro/src/@types/astro.ts

@@ -1115,6 +1115,10 @@ export interface AstroUserConfig {
 		 *   }
 		 * }
 		 * ```
+		 *  
+		 *  :::caution[Breaking changes possible]
+		 *  This feature is stable and is not considered experimental. However, this feature is only intended to address difficult performance issues, and breaking changes may occur in a [minor release](https://docs.astro.build/en/upgrade-astro/#semantic-versioning) to keep this option as performant as possible. Please check the [Astro CHANGELOG](https://github.com/withastro/astro/blob/refs/heads/next/packages/astro/CHANGELOG.md) for every minor release if you are using this feature.
+		 *  :::
 		 */
 		concurrency?: number;
 	};