Fix to prefer flow over definitions, setext headings

An undocumented part of CommonMark is how to deal with things in definition
labels or definition titles (which both can span multiple lines).
Can flow (or containers?) interrupt them?
They can according to the `cmark` reference parser, so this was implemented here.

This adds a new `Content` content type, which houses zero or more definitions,
and then zero-or-one paragraphs.
Content can be followed by a setext heading underline, which either turns
into a setext heading when the content ends in a paragraph, or turns into
the start of the following paragraph when it is followed by content that
starts with a paragraph, or turns into a stray paragraph.

1 files changed, 3 insertions, 1 deletions

diff --git a/src/construct/mod.rs b/src/construct/mod.rs
index 1afa105..ae6facf 100644
--- a/src/construct/mod.rs
+++ b/src/construct/mod.rs
@@ -16,7 +16,7 @@
 //! Content types also have a *rest* thing: after all things are parsed,
 //! there’s something left.
 //! In document, that is [flow][].
-//! In flow, that is a [paragraph][].
+//! In flow, that is [content][].
 //! In string and text, that is [data][partial_data].
 //!
 //! ## Construct
@@ -37,6 +37,7 @@
 //! *   [character escape][character_escape]
 //! *   [character reference][character_reference]
 //! *   [code (indented)][code_indented]
+//! *   [content][]
 //! *   [definition][]
 //! *   [hard break (escape)][hard_break_escape]
 //! *   [heading (atx)][heading_atx]
@@ -149,6 +150,7 @@ pub mod block_quote;
 pub mod character_escape;
 pub mod character_reference;
 pub mod code_indented;
+pub mod content;
 pub mod definition;
 pub mod document;
 pub mod flow;