chore: Document default strategy (#4010)

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Documenting Default Strategy 
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Closes #
[1-1023](https://linear.app/unleash/issue/1-1023/document-strategy-improvements)

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---------

Signed-off-by: andreas-unleash <andreas@getunleash.ai>
Co-authored-by: Thomas Heartman <thomas@getunleash.ai>

website/docs/reference/change-requests.md

@@ -20,7 +20,7 @@ This article contains all the details about how change requests work in Unleash;
 
 Feature flagging is a powerful tool, and because it's so powerful, you sometimes need to practice caution. The ability to have complete control over your production environment comes at the cost of the potential to make mistakes in production. Change requests were introduced in version 4.19.0 to alleviate this fear. Change requests allow you to group changes together and apply them to production at the same time, instead of applying changes directly to production. This allows you to make multiple changes to feature toggles and their configuration and status (on/off) all at once, reducing the risk of errors in production.
 
-Our goal is developer effeciency, but we also recognize that we have users and customers in highly regulated industries, governed by law and strict requirements. Therefore, we have added a capability to change requests that will allow you to enforce the _4 eyes principle_.
+Our goal is developer efficiency, but we also recognize that we have users and customers in highly regulated industries, governed by law and strict requirements. Therefore, we have added a capability to change requests that will allow you to enforce the _4 eyes principle_.
 
 ## Change request configuration
 

website/docs/reference/projects.md

@@ -98,3 +98,26 @@ All available projects are available from the drop-down menu.
 If you want to change which project a feature toggle belongs to, you can change that from the feature toggle's configuration page. Under the _settings_ tab, choose the _project_ option and choose the new project from the dropdown menu.
 
 ![A feature toggle's settings tab. The project setting shows a dropdown to change projects.](/img/projects_existing_toggle_dropdown.png)
+
+## Project default strategy
+import Figure from '@site/src/components/Figure/Figure.tsx'
+
+:::info Availability
+
+The project default strategy feature is generally available starting with **Unleash 5.2.0**.
+
+:::
+
+You can define default strategies for each of a project's environments. The default strategy for an environment will be added to a feature when you enable it in an environment **if and only if** the feature has **no active strategies** defined.
+
+All default project strategies use the [gradual rollout activation strategy](activation-strategies.md). By default, the rollout 100%. You can customize the strategies by changing the rollout percentage and adding [constraints](strategy-constraints.md) and [segments](segments.mdx) as you would for any other strategy.
+
+### Configuration
+
+Custom strategies are configured from each project's project settings tab.
+
+<Figure caption="The default strategy configuration page is available from the project settings tab." img="/img/project-settings-default-sstrategy.png" />
+
+The default strategies screen lists a strategy for each of the project's environments
+
+<Figure caption="Each strategy can be individually configured with the corresponding edit button." img="/img/edit-default-strategy.png" />