document add_depends dependency type interface

diff --git a/doc/plugins/write.mdwn b/doc/plugins/write.mdwn
index 668f8d8b69dff65acc0727fa5fa3233e516b132a..c244c1f2fd68a92eb325d3b209594b3b35f85768 100644 (file)
--- a/doc/plugins/write.mdwn
+++ b/doc/plugins/write.mdwn
@@ -609,10 +609,17 @@ page created from it. (Ie, it appends ".html".)
 Use this when constructing the filename of a html file. Use `urlto` when
 generating a link to a page.
 
-#### `add_depends($$)`
+#### `add_depends($$;@)`
 
 Makes the specified page depend on the specified [[ikiwiki/PageSpec]].
 
+Additional named parameters can be passed, to indicate what type of
+dependency this is.
+
+Currently, only a "content" parameter is specified. If set to 0, the
+dependency does not involve the content of pages matching the PageSpec, but
+only their existence.
+
 #### `pagespec_match($$;@)`
 
 Passed a page name, and [[ikiwiki/PageSpec]], returns true if the