Fixes some nits and blog post link in upgrade-to/v6.mdx (#13618)

Co-authored-by: louisescher <66965600+louisescher@users.noreply.github.com>

Author: ArmandPhilippot

src/content/docs/en/guides/upgrade-to/v6.mdx

@@ -472,7 +472,7 @@ If you are an adapter author with a public repository and [include the `astro-ad
 
 If you are seeing warnings because you are using a community adapter that is not yet updated, please reach out to the adapter author directly to let them know. It is ultimately their responsibility to update their adapters. You can also let the Astro core team know in the [`#integrations` channel of our Discord](https://astro.build/chat) and we will attempt to help the adapter author upgrade.
 
-If you have built an adapter, follow these steps to remove the legacy v5 behaviour:
+If you have built an adapter, follow these steps to remove the legacy v5 behavior:
 
 <Steps>
 
@@ -592,7 +592,7 @@ Rename and move this file to `src/content.config.ts`
 </details>
 
 <details>
-<summary>a collection that does not define a `loader`/ ([`ContentCollectionMissingALoaderError`](/en/reference/errors/content-collection-missing-loader/))</summary>
+<summary>a collection that does not define a `loader` / ([`ContentCollectionMissingALoaderError`](/en/reference/errors/content-collection-missing-loader/))</summary>
 
 Import [Astro's built-in `glob()` loader](/en/guides/content-collections/#the-glob-loader) and define the `pattern` and `base` for your collection entries:
 
@@ -946,7 +946,7 @@ Astro 6.0 removes this signature entirely. Attempting to pass these separate arg
 
 #### What should I do?
 
-Review your `app.render` calls and pass `routeData` and `locals` as properties of an object instead of as multiple independent arguments:
+Review your `app.render()` calls and pass `routeData` and `locals` as properties of an object instead of as multiple independent arguments:
 
 ```ts title="my-adapter/entrypoint.ts" del={1} ins={2}
 app.render(request, routeData, locals)
@@ -1022,7 +1022,7 @@ prefetch('/about');
 
 <SourcePR number="14477" title="feat!: remove rewrite from action context"/>
 
-In Astro 5.5.6, the `ActionAPIContext.rewrite` method was deprecated because custom endpoints should be used instead of rewrites.
+In Astro 5.5.6, the `ActionAPIContext.rewrite()` method was deprecated because custom endpoints should be used instead of rewrites.
 
 Astro 6.0 removes the `rewrite()` method from `ActionAPIContext` entirely and it may no longer be used.
 
@@ -1172,7 +1172,7 @@ export default defineConfig({
 - `staticImportMetaEnv` (See below for breaking changes to [`import.meta.env`](#changed-importmetaenv-values-are-always-inlined).)
 - `headingIdCompat` (See below for breaking changes to [Markdown heading ID generation](#changed-markdown-heading-id-generation).)
 
-<ReadMore>Read about exciting new features and more in [the v6.0 Blog post](https://astro.build/blog/astro-6-beta/).</ReadMore>
+<ReadMore>Read about exciting new features and more in [the v6.0 Blog post](https://astro.build/blog/astro-6/).</ReadMore>
 
 ## Changed Defaults
 
@@ -1414,7 +1414,7 @@ If you were previously relying on the fact that the image service would automati
 />
 ```
 
-<ReadMore>Learn more about [the `format` image property](/en/reference/modules/astro-assets/#format)</ReadMore>
+<ReadMore>Learn more about [the `format` image property](/en/reference/modules/astro-assets/#format).</ReadMore>
 
 ### Changed: `getImage()` throws when called on the client
 
@@ -1612,7 +1612,7 @@ export function getStaticPaths() {
 
 <SourcePR number="14895" title="feat: remove Vitest workaround for client environment"/>
 
-In Astro 5.x, rendering an Astro component on the client was forbidden. However we temporarily allowed this behavoir in Vitest client environments such as `jsdom` or `happy-dom` using the [experimental Container API](/en/reference/container-reference/).
+In Astro 5.x, rendering an Astro component on the client was forbidden. However we temporarily allowed this behavior in Vitest client environments such as `jsdom` or `happy-dom` using the [experimental Container API](/en/reference/container-reference/).
 
 Astro 6.0 removes the ability to render Astro components in Vitest client environments: tests that render Astro components must now run in a server environment like `node`.