fix text in HTTP API page (#1455)

website/HTTP API.md

@@ -9,7 +9,7 @@ The API:
   * (optional) `X-Last-Modified` the last modified time of the file as a UNIX timestamp in ms since the epoch (as coming from `Data.now()`). This timestamp _has_ to match the `lastModified` listed for this file in `/index.json` otherwise syncing issues may occur. When this header is missing, frequent polling-based sync will be disabled for this file.
   * (optional) `X-Created` the created time of the file as a UNIX timestamp in ms since the epoch (as coming from `Data.now()`).
   * (optional) `X-Permission`: either `rw` or `ro` which will change whether the editor opens in read-only or edit mode. When missing, `ro` is assumed.
-  * (opti[space_server.ts](../server/space_server.ts)onal) `X-Content-Length`: which will be the same as `Content-Length` except if the request was sent with a `X-Get-Meta` header and the body is not returned (then `Content-Length` will be `0` and `X-Content-Length` will be the size of the file)
+  * (optional) `X-Content-Length`: which will be the same as `Content-Length` except if the request was sent with a `X-Get-Meta` header and the body is not returned (then `Content-Length` will be `0` and `X-Content-Length` will be the size of the file)
 * `PUT /*.*`: The same as `GET` except that it takes the body of the request and _writes_ it to a file.
 * `DELETE /*.*`: Again the same, except this will _delete_ the given file.
 * `GET /*` and `GET /`: Anything else (any path without a file extension) will serve the SilverBullet UI HTML.
@@ -20,4 +20,4 @@ The API:
   * `indexPage`: name of the index page
 * `GET /.ping`: Returns 200 if the server is available
 * `POST /.shell`: Run a shell command on the server side and return the result
-* `* /.proxy/<uri>`: Proxy a HTTP request (to avoid CORS issues) 
+* `* /.proxy/<uri>`: Proxy a HTTP request (to avoid CORS issues)