Add group wikis import export to docs

doc/api/group_import_export.md

@@ -20,6 +20,7 @@ Group exports include the following:
 - Group badges
 - Group members
 - Sub-groups. Each sub-group includes all data above
+- Group wikis **(PREMIUM SELF)**
 
 ## Schedule new export
 

doc/user/group/index.md

@@ -466,7 +466,7 @@ Group wiki repositories can be moved through the [Group repository storage moves
 There are a few limitations compared to project wikis:
 
 - Git LFS is not supported.
-- Group wikis are not included in global search, group exports, and Geo replication.
+- Group wikis are not included in global search and Geo replication.
 - Changes to group wikis don't show up in the group's activity feed.
 
 For updates, you can follow:

doc/user/group/settings/import_export.md

@@ -48,6 +48,7 @@ The following items are exported:
 - Subgroups (including all the aforementioned data)
 - Epics
 - Events
+- Wikis **(PREMIUM SELF)** (Introduced in [GitLab 13.9](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/53247))
 
 The following items are **not** exported: