docs: revise BBS SuspectCells metric description
[#159770580](https://www.pivotaltracker.com/story/show/159770580)
@@ -61,7 +61,7 @@ A list of component-level metrics emitted by Diego. Contributors interested in a
| `PresentCells` | Total number of cells that are maintaining presence with Locket. Emitted periodically.
| `RequestCount` | Cumulative number of requests the BBS has handled through its API. Emitted periodically. | number | |
| `RequestLatency` | Maximum amount of time the BBS took to handle a request to one its API endpoints over a 60-second interval. Emitted every 60 seconds. | ns | |
-| `SuspectCells` | Total number of cells that are not maintaining presence with Locket. Emitted periodically.
+| `SuspectCells` | Total number of cells that are not maintaining their presences with Locket but for which the BBS has a record of at least one ActualLRP. Emitted periodically.
| `SuspectClaimedActualLRPs` | Total number of Suspect LRP instances that have been claimed by some cell. Emitted periodically. | number | |
| `SuspectRunningActualLRPs` | Total number of Suspect LRP instances that are running on cells. Emitted periodically. | number | |
| `TasksCompleted` | Total number of Tasks that have completed. Emitted periodically. | number | |
