Close #501

Fix #396

Fix #495

Ensure root output directory exists explicitly.

Aliases that have no directory nesting sneakily avoid the code path that ensures the directories exist

Remove unmatchable rules from render_shortcodes

Fix #490

Closes #486

Closes #485

Local CSV/TOML/JSON loading Tera function

section.subsections is now an array of paths

prevent html tags from appearing in the toc

Close #446
Close #260
Close #478
Close #284
Close #480

Add F# syntax highlighting.

Fix #445

Fix content parser's 'text' rule to use the correct production

Can't remember why it was doing that even
with the comment and the test added in the
commit still pass so...

Fix #462

Allow inclusion of all items in RSS feeds.

Switch to an `Option<usize>` for the serialized value of `rss_items`.
This lets us just set a blank value in the configuration and thereby
include *all* items.

This is a backwards-compatible change; it does not affect the behavior
of existing configurations.

Fixes #468. Closes #471.

Slotmap refactor