feat(alerts): Add anomaly detection docs

Author: ceorourke

docs/organization/early-adopter-features/index.mdx

@@ -21,3 +21,4 @@ Limitations:
 - [Span Summary](/product/performance/transaction-summary/#span-summary)
 - [Investigation Mode](/product/performance/retention-priorities/#investigation-mode) for retention priorities in Tracing
 - [Uptime Monitoring](/product/alerts/uptime-monitoring/)
+- [Dynamic Alerts](/product/alerts/create-alerts/metric-alert-config/#dynamic-alerts)

docs/product/alerts/alert-types.mdx

@@ -37,6 +37,10 @@ The **Alert Details** page also includes a list of issues that triggered the ale
 
 Metric alerts tell you when a [metric](/product/performance/metrics/) crosses a threshold set by you, like a spike in the number of errors in a project, or a change in a performance metric, such as [transaction duration](/product/performance/metrics/#latency), [Apdex](/product/performance/metrics/#apdex), [failure rate](/product/performance/metrics/#failure-rate), or [throughput](/product/performance/metrics/#throughput-total-tpm-tps).
 
+<Note>
+You can use [dynamic alerts](/product/alerts/create-alerts/metric-alert-config/#dynamic-alerts) to let Sentry define the threshold for you.
+</Note>
+
 Metric alerts monitor macro-level metrics for both error and transaction events. A metric takes a set of events and computes an aggregate value using a function, such as `count()` or `avg()`, applied to the event properties over a period of time. When you create a metric alert, you can filter events by attributes and <PlatformLink to="/enriching-events/tags/">tags</PlatformLink>, which is particularly useful for aggregating across events that aren't grouped into single issues. Sentry allows a maximum of 1000 metric alerts for an organization.
 
 <Note>

docs/product/alerts/create-alerts/metric-alert-config.mdx

@@ -113,10 +113,11 @@ While Sentry won’t allow you to create new alerts with invalid or unavailable
 
 ## Thresholds
 
-There are two threshold types:
+There are three threshold types:
 
 - **Static**: A fixed threshold, such as when there are 100 errors in a period of time.
-- **Percent change**: A dynamic threshold, such as when there are 10% more errors in a time period compared to a previous period. These are also referred to as [Change Alerts](#change-alerts-percent-change).
+- **Percent change**: A percent based threshold, such as when there are 10% more errors in a time period compared to a previous period. These are also referred to as [Change Alerts](#change-alerts-percent-change).
+- **Dynamic**: A dynamic threshold set by Sentry that detects anomalies whenever values fall outside expected bounds.
 
 By default, metric alerts use a fixed threshold.
 
@@ -128,6 +129,18 @@ Change alerts, or alerts that use a percent change threshold, are useful when yo
 
 ![When the percent change option is selected.](./img/percent-change.png)
 
+### Dynamic Alerts
+
+<Include name="feature-available-for-user-group-early-adopter.mdx" />
+
+Dynamic alerts can be used when you don't know what threshold to set, but you know you want to be alerted when something is far outside the bounds of normalcy. Sentry will look at the historical data for the given metric and determine if the current data is anomalous. You can select how responsive the alert will be, and whether you want to be alerted when the metric is above, below, or both above and below the expected bounds.
+
+Dynamic alerts do not use the Critical, Warning, and Resolved thresholds like other alert threshold types as you are not setting these yourself. When no more anomalies are detected, the alert will resolve.
+
+TODO update this image when deploy is finished
+
+![When the percent change option is selected.](./img/percent-change.png)
+
 ### Set Threshold to Trigger Alert
 
 You can set the status of an alert rule when a threshold is met using the labels: