swarm-wire: say the repos list holds only repositories with an open issue

docs/swarm/notify-router.md

@@ -112,8 +112,9 @@ accepts:
   lists the accepted `{name, description}` pairs (the `upsert` and `clear` of a
   todo's `op`), empty for other fields.
 - `values_from` on a field says where an editor asks for values that are only
-  known live: `agents` is the names `GET /api/agents` lists, `repos` the ones
+  known live: `agents` is the names `GET /api/agents` lists, `repos` the
-  `GET /api/repos` lists. `closed` says `values` and that source are every value
+  repositories with an open issue, which `GET /api/repos` lists, so a repository
+  with none is missing. `closed` says `values` and that source are every value
   the field takes, which an editor can show as a dropdown. When false, they
   are suggestions: the field still takes any other text, such as an `action` the
   forge adds later or the login of a reviewer who is no agent.

docs/swarm/ui.md

@@ -299,7 +299,8 @@ controller's own message. The router runs a saved flow from its next event.
 Where the controller's schema knows the values, the editor offers them instead of
 asking you to type a name: `kind` and `event` conditions and the todo's `op` are
 dropdowns, `action` and `repo` conditions and a reviewer are boxes that list the
-known values to pick from and still take any other text, and a todo's agent is a
+known values to pick from and still take any other text (the repositories listed
+are those with an open issue, so one with none is missing), and a todo's agent is a
 dropdown of the swarm's agents. A value set in a flow that the list no longer
 holds stays selected, marked "not listed." If a list fails to load, or the
 controller predates the schema, the box is plain text. The values come from the

swarm-wire/src/notify_flows.rs

@@ -362,7 +362,9 @@ pub struct Described {
 /// them.
 pub const VALUES_FROM_AGENTS: &str = "agents";
 
-/// `values_from` marker: the repositories, as `GET /api/repos` lists them.
+/// `values_from` marker: the repositories with an open issue, as
+/// `GET /api/repos` lists them. A repository with none is missing, so a field
+/// that takes this marker is never closed.
 pub const VALUES_FROM_REPOS: &str = "repos";
 
 /// The `kind` field's values: what the router puts there, which is not the