function is passed no values. It's ok for the function to call
`error()` if something isn't configured right.
+### refresh
+
+ hook(type => "refresh", id => "foo", call => \&refresh);
+
+This hook is called just before ikiwiki scans the wiki for changed files.
+It's useful for plugins that need to create or modify a source page. The
+function is passed no values.
+
### needsbuild
hook(type => "needsbuild", id => "foo", call => \&needsbuild);
-This allows a plugin the manipulate the list of files that need to be
+This allows a plugin to manipulate the list of files that need to be
built when the wiki is refreshed. The function is passed a reference to an
array of pages that will be rebuilt, and can modify the array, either
adding or removing files from it.