Repository: tektoncd/pipeline (language: go)

Issue:
document pipelineRun status
With [TEP-00100](https://github.com/tektoncd/community/blob/main/teps/0100-embedded-taskruns-and-runs-status-in-pipelineruns.md), Pipelines API will be loosing direct access to `taskRun`/`run` status in `pipelineRun` status. At the same time, when we are trying to release `V1`, it becomes essential to provide in depth documentation on how to retrieve all these fields after 
[TEP-00100](https://github.com/tektoncd/community/blob/main/teps/0100-embedded-taskruns-and-runs-status-in-pipelineruns.md) is implemented.

Please create a new markdown `status.md` under [docs](https://github.com/tektoncd/pipeline/tree/main/docs) documenting the new `status` and mechanism to retrieve full status. 

References:

* https://github.com/tektoncd/pipeline/issues/3140
* https://github.com/tektoncd/pipeline/issues/3792

/kind documentation


Discussion / hints:
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/remove-lifecycle stale
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Fix patch:
diff --git a/docs/pipelineruns.md b/docs/pipelineruns.md
index d2dba0ce248..1f9e0b077d4 100644
--- a/docs/pipelineruns.md
+++ b/docs/pipelineruns.md
@@ -1387,6 +1387,8 @@ Your `PipelineRun`'s `status` field can contain the following fields:
     - [`apiVersion`][kubernetes-overview] - The API version for the underlying `TaskRun` or `Run`.
     - [`whenExpressions`](pipelines.md#guard-task-execution-using-when-expressions) - The list of when expressions guarding the execution of this task.
   - `provenance` - Metadata about resources used in the PipelineRun such as the source from where a remote pipeline definition was fetched.
+  - `finallyStartTime`- The time at which the PipelineRun's `finally` Tasks, if any, began
+  executing, in [RFC3339](https://tools.ietf.org/html/rfc3339) format.
 
 ### Configuring usage of `TaskRun` and `Run` embedded statuses
 


Test patch: