**User Story**
As a client developer, I want a unified API for editing article title descriptions that abstracts away the complexity of the underlying description sources
**Background**
For every Wikipedia except English Wikipedia, the article description included in the [[ https://de.wikipedia.org/api/rest_v1/#/Page%20content/get_page_summary__title_ | page summary ]] is from Wikidata. For English Wikipedia, as described in T256817, it now must come from the short description template in the article. It'd be ideal to have a single API for editing this title description that handles the underlying complexity of either editing Wikidata or English Wikipedia.
**Rough Spec**
Treat the `/page/summary` response as "editable" through a `POST` request. This will only work for `description` to start, so if any keys other than `description` are included in the request, it should error out.
Authenticated `POST /page/summary/Philadelphia` request with body parameter `description` set to `Largest city in Pennsylvania`
On enwiki, find the` {{short description}}` or `{{SHORTDESC}}` template in the wikitext and edit it. If it doesn't exist, add it. There are cases where the template is included through another template and it won't be in the wikitext for the given article. In those cases it should be added to the article's wikitext as well.
On all other wikis, edit the Wikidata description with `action=wbsetdescription`.