include more details on pod deletion for timed out and cancelled Task…

…Runs

docs/taskruns.md

@@ -254,18 +254,23 @@ For more information, see the [`LimitRange` code example](../examples/v1beta1/ta
 
 ## Configuring the failure timeout
 
-You can use the `timeout` field to set the `TaskRun's` desired timeout value in minutes.
-If you do not specify this value in the `TaskRun`, the global default timeout value applies.
-If you set the timeout to 0, the `TaskRun` fails immediately upon encountering an error.
+You can use the `timeout` field to set the `TaskRun's` desired timeout value. If you do not specify this 
+value for the `TaskRun`, the global default timeout value applies. If you set the timeout to 0, the `TaskRun` will 
+have no timeout and will fail immediately upon encountering an error.
 
 The global default timeout is set to 60 minutes when you first install Tekton. You can set
 a different global default timeout value using the `default-timeout-minutes` field in
-[`config/config-defaults.yaml`](./../config/config-defaults.yaml).
+[`config/config-defaults.yaml`](./../config/config-defaults.yaml). If you set the global timeout to 0, 
+all `TaskRuns` that do not have a timeout set will have no timeout and will fail immediately upon 
+encountering an error.
 
 The `timeout` value is a `duration` conforming to Go's
 [`ParseDuration`](https://golang.org/pkg/time/#ParseDuration) format. For example, valid
-values are `1h30m`, `1h`, `1m`, and `60s`. If you set the global timeout to 0, all `TaskRuns`
-that do not have an individual timeout set will fail immediately upon encountering an error.
+values are `1h30m`, `1h`, `1m`, and `60s`. 
+
+If a `TaskRun` runs longer than its timeout value, the pod associated with the `TaskRun` will be deleted. This 
+means that the logs of the `TaskRun` are not preserved. The deletion of the `TaskRun` pod is necessary in order to 
+stop `TaskRun` step containers from running. 
 
 ### Specifying `ServiceAccount' credentials
 
@@ -367,9 +372,13 @@ Status:
 
 ## Cancelling a `TaskRun`
 
-To cancel a `TaskRun` that's currently executing, update its definition
-to mark it as cancelled. When you do so, all running `Pods` associated with
-that `TaskRun` are deleted. For example:
+To cancel a `TaskRun` that's currently executing, update its status to mark it as cancelled. 
+
+When you cancel a TaskRun, the running pod associated with that `TaskRun` is deleted. This 
+means that the logs of the `TaskRun` are not preserved. The deletion of the `TaskRun` pod is necessary 
+in order to stop `TaskRun` step containers from running. 
+
+Example of cancelling a `TaskRun`:
 
 ```yaml
 apiVersion: tekton.dev/v1alpha1