docs: add generated plugin reference pages

docs/plugins/reference/searxng.md

@@ -0,0 +1,19 @@
+---
+summary: "Adds web search provider support."
+read_when:
+  - You are installing, configuring, or auditing the searxng plugin
+title: "SearXNG plugin"
+---
+
+# SearXNG plugin
+
+Adds web search provider support.
+
+## Distribution
+
+- Package: `@openclaw/searxng-plugin`
+- Install route: included in OpenClaw
+
+## Surface
+
+contracts: webSearchProviders