clip: add page (#2397)

pages/windows/clip.md

@@ -0,0 +1,11 @@
+# clip
+
+> Copy input content to the Windows clipboard.
+
+- Pipe command line output to the Windows clipboard:
+
+`{{dir}} | clip`
+
+- Copy the contents of a file to the Windows clipboard:
+
+`clip < {{path/to/file}}`