Add acp search result provider PIP documentation

pages/package/pip/package_pip_acp-search-provider.md

@@ -6,4 +6,33 @@ folder: package/pip
 parent: package_pip
 ---
 
-*Content will follow soon*
+Registers data provider for the admin panel search.
+
+## Components
+
+Each acp search result provider is described as an `<acpsearchprovider>` element with the mandatory attribute `name`.
+
+### `<classname>`
+
+The name of the class providing the search results.
+The class has to implement the `wcf\system\search\acp\IACPSearchResultProvider` interface.
+
+### `<showorder>`
+
+{% include callout.html content="Optional" type="info" %}
+
+Determines at which position of the search result list the provided results are shown.
+
+## Example
+
+```xml
+<?xml version="1.0" encoding="UTF-8"?>
+<data xmlns="http://www.woltlab.com" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.woltlab.com http://www.woltlab.com/XSD/vortex/acpSearchProvider.xsd">
+	<import>
+		<acpsearchprovider name="com.woltlab.wcf.example">
+			<classname>wcf\system\search\acp\ExampleACPSearchResultProvider</classname>
+			<showorder>1</showorder>
+		</acpsearchprovider>
+	</import>
+</data>
+```