Add idea in ideas.md

ideas.md

@@ -19,6 +19,7 @@ Flexible Static Site Generator
   * Rename `subDirs` to `dirs`, etc.?
   * An `after` function defined in __config__.py that gets run after all children are processed.
   * Installing pip requirements.txt for the site being built.
+  * Maybe: Expose `content` for user post-processing functions.
 * Top 2:
   * Add a trailing `/` slash for Markdown page dirs since: (a) if a Markdown page is turned into a dir/collection of smaller essays, this would allow that change to happen naturally/seamlessly, and (b) since many web servers including the one used by GH pages add a trailing `/` slash to directories using a 301 Redirect anyways.
   * Caching in the GitHub action. See: