As a watchlist expiry user, I want to be able to watch a page via edit, so that I can temporarily watch a page after a recent edit.
**Resources:**
* [[ https://meta.wikimedia.org/wiki/Community_Tech/Watchlist_Expiry | Watchlist Expiry project page ]]
* [[ https://wikimedia.invisionapp.com/public/share/J911SKRX3U#/screens/475686102 | Interactive mockup: Watch a page temporarily (via edit) ]]
**Acceptance Criteria:**
* In wikitext edit view, add the following:
** A new label to the right of watchlist checkbox: "Watchlist time period:"
** A drop-down to the right of label (inactive by default, before box checked)
* When user checks the box to "Watch this page," the drop-down should become active
* The user should be able to select watch period via drop-down
** The drop-down has the following options:
*** Permanently (as default)
*** for 1 week
*** for 1 month
*** for 3 months
*** for 6 months
* If the page has already been watched, the behavior should be as follows:
** Drop-down should have days left as pre-selected option at top
** The selection should be written as follows: "X days left" (for example, "10 days left" or "20 days left").
* If the page has already been watched with a selected temporary time period, and the user clicks "Publish" without changing the time period selection, no changes to the watch period should be made.
* The watch period should be saved or updated, if the user makes a new watch selection.
**Visual Example:**
{F31718243}