Docs: Add shared (#28411)

* added content

* Update example.md

* Update example.md

docs/sources/shared/example.md

+---
+title: Shared Content
+---
+
+```
+npm i
+```
+
+Syntax to invoke this file would be:
+
+```
+{{< docs/shared "example" >}}
+```
\ No newline at end of file

docs/sources/shared/index.md

+---
+headless: true
+---
+
+
+
+