docs(router): using square brackets for character escaping (#4753)

Author: Balastrong

docs/router/framework/react/routing/file-naming-conventions.md

@@ -13,6 +13,7 @@ File-based routing requires that you follow a few simple file naming conventions
 | **`_` Suffix**                     | Route segments with the `_` suffix exclude the route from being nested under any parent routes.                                                                                                                                                                                                                                                                                    |
 | **`-` Prefix**                     | Files and folders with the `-` prefix are excluded from the route tree. They will not be added to the `routeTree.gen.ts` file and can be used to colocate logic in route folders.                                                                                                                                                                                                  |
 | **`(folder)` folder name pattern** | A folder that matches this pattern is treated as a **route group**, preventing the folder from being included in the route's URL path.                                                                                                                                                                                                                                             |
+| **`[x]` Escaping**                 | Square brackets escape special characters in filenames that would otherwise have routing meaning. For example, `script[.]js.tsx` becomes `/script.js` and `api[.]v1.tsx` becomes `/api.v1`.                                                                                                                                                                                        |
 | **`index` Token**                  | Route segments ending with the `index` token (before any file extensions) will match the parent route when the URL pathname matches the parent route exactly. This can be configured via the `indexToken` configuration option, see [options](../../../../api/file-based-routing.md#indextoken).                                                                                   |
 | **`.route.tsx` File Type**         | When using directories to organise routes, the `route` suffix can be used to create a route file at the directory's path. For example, `blog.post.route.tsx` or `blog/post/route.tsx` can be used as the route file for the `/blog/post` route. This can be configured via the `routeToken` configuration option, see [options](../../../../api/file-based-routing.md#routetoken). |