fix(errors): align three error names with their documented reference

.changeset/olive-pans-shave.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fix three error names that did not match their documented reference. `MissingLocale`, `MissingIndexForInternationalization` and `NoManifestAvailable` reported names ending in `Error` in the dev overlay, while their error reference pages are published under the unsuffixed names, so the name shown to users could not be found in the docs.

packages/astro/src/core/errors/errors-data.ts

@@ -1188,7 +1188,7 @@ export const FailedToFindPageMapSSR = {
  * Astro can't find the requested locale. All supported locales must be configured in [`i18n.locales`](https://docs.astro.build/en/reference/configuration-reference/#i18nlocales) and have corresponding directories within `src/pages/`.
  */
 export const MissingLocale = {
-	name: 'MissingLocaleError',
+	name: 'MissingLocale',
 	title: 'The provided locale does not exist.',
 	message: (locale: string) =>
 		`The locale/path \`${locale}\` does not exist in the configured \`i18n.locales\`.`,
@@ -1203,7 +1203,7 @@ export const MissingLocale = {
  * - [`i18n.routing` Configuration Reference](https://docs.astro.build/en/reference/configuration-reference/#i18nrouting)
  */
 export const MissingIndexForInternationalization = {
-	name: 'MissingIndexForInternationalizationError',
+	name: 'MissingIndexForInternationalization',
 	title: 'Index page not found.',
 	message: (defaultLocale: string) =>
 		`Could not find index page. A root index page is required in order to create a redirect to the index URL of the default locale. (\`/${defaultLocale}\`)`,
@@ -1567,7 +1567,7 @@ export const LoggerConfigurationNotSerializable = {
  * `new FetchState(request)` was called outside of an Astro server, so no manifest is available.
  */
 export const NoManifestAvailable = {
-	name: 'NoManifestAvailableError',
+	name: 'NoManifestAvailable',
 	title: 'No manifest available.',
 	message:
 		'`new FetchState(request)` was called outside of an Astro server, so no manifest is available.',

packages/astro/test/units/manifest/ambient.test.ts

@@ -20,7 +20,7 @@ describe('ambient manifest', () => {
 			() => getAmbientManifest(),
 			(error: unknown) => {
 				assert.ok(error instanceof Error);
-				assert.equal(error.name, 'NoManifestAvailableError');
+				assert.equal(error.name, 'NoManifestAvailable');
 				assert.match(error.message, /outside of an Astro server/);
 				return true;
 			},