Mention kapp default update strategy flag in faq

Add mention of the kapp `--apply-default-update-strategy` flag
to the FAQ and the annotation docs.

site/content/kapp/docs/develop/apply.md

@@ -43,6 +43,8 @@ In some cases entire resources or subset resource fields are immutable which for
 - `always-replace` causes kapp to always delete and then create resource (See note above as well.)
 - `skip` causes kapp to not apply update (it will show up in a diff next time). Available in v0.33.0+.
 
+There is also a CLI-wide flag `--apply-default-update-strategy`. If set, it will be used as a default value for all resources that do not have `kapp.k14s.io/update-strategy` annotation set. If used, consider explicitly annotating individual resources that should not be replaced with `""` or `"skip"`.
+
 ### kapp.k14s.io/delete-strategy
 
 `kapp.k14s.io/delete-strategy` annotation controls deletion behaviour

site/content/kapp/docs/develop/faq.md

@@ -29,6 +29,8 @@ See [state namespace](state-namespace.md) doc page.
 
 Some fields on a resource are immutable. kapp provides a `kapp.k14s.io/update-strategy` annotation that controls how kapp will update resource. One of the strategies is `fallback-on-replace` which will have kapp recreate an object (delete, wait, then create) if initial update results in `Invalid` error. See [Controlling apply via resource annotations](apply.md#controlling-apply-via-resource-annotations) for details.
 
+The CLI flag `--apply-default-update-strategy=fallback-on-replace` can be used to instruct `kapp` to default to this behavior for all resources. Consider specifically annotating specific resources you wish to protect from deletion if you use this.
+
 ---
 ## `Job.batch is invalid: ... spec.selector: Required value` error