feat(ACI): Mention issue stream monitor (#17146)

Add a mention of the issue stream detector and what it is for. This will
be linked to in the workflow POST and PUT docs.

Author: ceorourke

docs/product/new-monitors-and-alerts/monitors/index.mdx

@@ -8,7 +8,7 @@ sidebar_order: 70
  New Monitors and Alerts is currently in <strong>beta</strong>. Beta features are still a work in progress and may have bugs. We recognize the irony. Help improve this feature by providing feedback on our [GitHub discussion](https://github.com/getsentry/sentry/discussions/101960).
 </Alert>
 
-Sentry's Monitors are used to customize when to turn errors and performance problems into issues. They can be configured using conditional rules to create issues when specific criteria are met. For example, you could monitor when the duration of a transaction takes longer than 3 seconds on a particular browser. Further automate your issue creation experience using Monitors to automatically add assignees and set different priorities based on severity. 
+Sentry's Monitors are used to customize when to turn errors and performance problems into issues. They can be configured using conditional rules to create issues when specific criteria are met. For example, you could monitor when the duration of a transaction takes longer than 3 seconds on a particular browser. Further automate your issue creation experience using Monitors to automatically add assignees and set different priorities based on severity.
 
 ## Types of Monitors
 
@@ -22,8 +22,9 @@ You can use Custom Monitors to track errors based on span attributes and custom
 
 ### Default Monitors
 
-Sentry also provides default monitors that are automatically created for you when you create a new project. 
+Sentry also provides default monitors that are automatically created for you when you create a new project.
 
+- **Issue Stream Monitor**: The default monitor tracking new issues of all types created for a project
 - **Error Monitor**: The default monitor based on [issue grouping/fingerprint rules](/concepts/data-management/event-grouping/)
 - **Replay Monitor**: Once you've configured [Session Replay](/product/explore/session-replay/), issues will be created via the Replay Monitor
 - **Trace Monitor**: Once you've configured [Tracing](/product/tracing/), issues will be created via the Trace Monitor
@@ -57,7 +58,7 @@ Assignees set by [ownership rules](/product/issues/ownership-rules/) will overri
 
 ### Metric Monitor Settings
 
-Metric Monitors are used to track errors based on span attributes and custom metrics. 
+Metric Monitors are used to track errors based on span attributes and custom metrics.
 
 Choose the metric, the interval for how often to check, and the way you want to monitor for changes. You can choose an absolute number threshold, a percentage change, or dynamic anomaly detection.
 
@@ -83,7 +84,7 @@ Dynamic thresholds are good for when it’s cumbersome to create fixed threshold
 
 ### Cron Monitor Settings
 
-Cron Monitors are used to track the uptime and performance of any scheduled, recurring job. 
+Cron Monitors are used to track the uptime and performance of any scheduled, recurring job.
 
 Choose the schedule for how often to check, set the check-in margin, the max runtime, and failure tolerance. Learn how to set up a [Cron Monitor](/product/new-monitors-and-alerts/monitors/crons/getting-started/).
 
@@ -105,4 +106,4 @@ Monitors are a Project-level feature, but the permission set is organization-lev
 
 By clicking on a Monitor, you can view the details, edit the Monitor, or disable it.
 
-The details page will show a high level chart of the Monitor's performance, the configuration, created issue, and connected automations. 
+The details page will show a high level chart of the Monitor's performance, the configuration, created issue, and connected automations.