Remove 'experimental' from high-availability, and '.' from etcd bullet (#17254)

* Remove 'experimental' from high-availability, and '.' from etcd bullet

s/controller-managing/controller-manager
s/Apiserver/API server
s/Assuming/Assumes

* Update content/en/docs/tasks/debug-application-cluster/debug-cluster.md

Co-Authored-By: Stephen Augustus <justaugustus@users.noreply.github.com>

* Update content/en/docs/tasks/debug-application-cluster/debug-cluster.md

Co-Authored-By: Stephen Augustus <justaugustus@users.noreply.github.com>

* Update content/en/docs/tasks/debug-application-cluster/debug-cluster.md

Co-Authored-By: Stephen Augustus <justaugustus@users.noreply.github.com>

content/en/docs/tasks/debug-application-cluster/debug-cluster.md

@@ -100,11 +100,11 @@ This is an incomplete list of things that could go wrong, and how to adjust your
 - Action: Use IaaS providers reliable storage (e.g. GCE PD or AWS EBS volume) for VMs with apiserver+etcd
   - Mitigates: Apiserver backing storage lost
 
-- Action: Use (experimental) [high-availability](/docs/admin/high-availability) configuration
-  - Mitigates: Master VM shutdown or master components (scheduler, API server, controller-managing) crashing
+- Action: Use [high-availability](/docs/admin/high-availability) configuration
+  - Mitigates: Control plane node shutdown or control plane components (scheduler, API server, controller-manager) crashing
     - Will tolerate one or more simultaneous node or component failures
-  - Mitigates: Apiserver backing storage (i.e., etcd's data directory) lost
-    - Assuming you used clustered etcd.
+  - Mitigates: API server backing storage (i.e., etcd's data directory) lost
+    - Assumes HA (highly-available) etcd configuration
 
 - Action: Snapshot apiserver PDs/EBS-volumes periodically
   - Mitigates: Apiserver backing storage lost