feature: rust parser: MarkdownCursor.node().walk() should be a MarkdownCursor

[janWilejan]

tree-sitter-md = { version = "0.3.2", features = ["parser"] }

Node::walk() does not return a MarkdownCursor. This makes it hard to re-visit nodes.

let cursor : MarkdownCursor = ...

// Save a node to come back to
let node = cursor.node();

do_something_with_cursor(&mut cursor);

// Error
let re_visit: MarkdownCursor = node.walk();

Proposed solution:

• Add struct MarkdownNode as a thin wrapper around Node
  • Deref lets you use all the methods of Node
impl Deref for MarkdownNode { type Target = Node; ... }
  • Shadow walk to return a MarkdownCursor
impl MarkdownNode { fn walk(&self) -> MarkdownCursor { ... } }
• Change MarkdownCursor::node to return MarkdownNode. Or add a new method fn markdown_node(&self) -> MarkdownNode

[ObserverOfTime]

PR welcome.