Apply suggestions from code review

Co-authored-by: Stefaan Lippens <soxofaan@users.noreply.github.com>

Author: m-mohr

extensions/federation/README.md

@@ -111,7 +111,7 @@ schema:
 Every discoverable resource that is defined as an object and allows to contain additional properties, can list the subset of back-ends that permanently support or host the exposed resource/functionality.
 Examples of where this could apply to (**not** comprehensive):
 
-- `GET /collctions`
+- `GET /collections`
 - `GET /collections/{id}`
 - `GET /processes` (global, per process, per parameter)
 - `GET /file_formats` (global, per file format)
@@ -199,7 +199,7 @@ This also covers the case where the federation supports splitting a process into
 
 Resources and back-ends can be temporarily or unintentionally unavailable.
 It is especially important to communicate to users missing resources when compiling lists of resources across multiple back-ends.
-Clients will assume that all lists of resources are the a combination of all back-ends listed in `GET /`.
+Clients will assume that all lists of resources are the a combination of all back-ends listed under`federation` in `GET /`.
 Federated APIs can expose if any of the back-ends is temporarily not available and thus is not part of the response.
 
 Examples of where this could apply to (**not** comprehensive):
@@ -225,7 +225,7 @@ schema:
       description: >-
         Lists all back-ends that were temporarily not considered in the response (e.g. because they were not accessible).
         If not given or empty, all back-ends supporting this endpoint were considered for creating the response.
-        Back-ends that were listed as offline in the capabilities still need to be listed here.
+        Back-ends that are listed as offline in the capabilities still need to be listed here.
       type: array
       items:
         type: string