Refactor Parser trait to pass min_indent

This removes the need to explicitly pass thru min_indent when using the parser combinators.

My ultimate goal here is to evolve the current parser closer toward a purely combinator-based parser,
at which point we can more easily transition smoothly to a formal(ish) grammar, or expand the meanings of combinators
to include things like:
* Incremental (re)parsing
* Unified parsing and formatting code
* Better error recovery
* Using the main parser directly for syntax highlighting

crates/docs/src/lib.rs

@@ -870,7 +870,7 @@ fn markdown_to_html(
                 // more memory as we iterate through these.
                 arena.reset();
 
-                match parse_ident(&arena, state) {
+                match parse_ident(&arena, state, 0) {
                     Ok((_, Ident::Access { module_name, parts }, _)) => {
                         let mut iter = parts.iter();