Say in a condition's message which issue tracks it and where that issue stands (issue 400)

The operator could not tell from a notification whether its cause was
known, tracked and being fixed, or whether they had to act. The issue
tracker gains the verb tracking, answering for every condition key an
issue links which issues link it and where each stands; the operator
channel's router asks it outside the work and says one line from it in
every condition's message, per hq ADR 0285.

modules/mesh-issues/module.json

@@ -15,7 +15,8 @@
         "link",
         "import",
         "groom",
-        "set"
+        "set",
+        "tracking"
       ]
     }
   ],
@@ -32,7 +33,8 @@
         "link",
         "import",
         "groom",
-        "set"
+        "set",
+        "tracking"
       ]
     }
   ],