feat: follow Markdown file links and heading fragments

docs/editing.md

@@ -16,6 +16,7 @@ Default controls and editing behavior. For custom bindings, see [configuration](
 | Normal, Visual | `I` (Shift+i) / `A` (Shift+a) insert at first nonblank / line end; Visual splits each touched row into a caret first |
 | Normal | `h`/`j`/`k`/`l` or arrows move every caret; `0`/`$` or Home/End |
 | Normal | `w`/`b`/`e` move every caret to next word start, previous/current word start, word end; `W`/`B`/`E` for whitespace-delimited WORDs |
+| Normal | `gf` follows a Markdown file link or heading fragment at the primary caret |
 | Normal, Visual | Decimal prefixes repeat cursor/word/search motions: `5j`, `3k`, `2w`, `4e`, `2n`; Esc cancels a pending count |
 | Normal | `J` (Shift+j) joins each targeted line with the next line |
 | Normal | `x`/Delete delete; `u` undo; `U` (Shift+u) redo; `:` enter command mode |
@@ -170,6 +171,22 @@ Esc or Ctrl+p cancels without changing text, selections, the previous command/se
 
 Space begins a leader sequence in Normal/Visual by default. Press the suffix keys in order; nested prefixes wait without a timeout. The status bar shows the pending sequence. Esc cancels the sequence and pending count without leaving Visual or collapsing carets. See [leader configuration](configuration.md#leader-key) for remapping and declaration rules.
 
+## Markdown links
+
+Normal `gf` or `:follow_link` follows the link under the primary caret, without an LSP. Inline links and full/collapsed/shortcut reference links are supported; reference definitions can appear elsewhere in the document. The label or destination can be under the caret. Images, code blocks, and ordinary text are not file links.
+
+Local paths resolve relative to the source file, not the working directory; percent-encoded UTF-8 paths and Markdown-escaped punctuation are decoded. Targets can be any supported text file. Existing buffers are reused, including unsaved text and files removed from disk. Missing files, undefined references, invalid destinations, or missing headings report an error without switching buffers or moving carets.
+
+`[Section](#section)` stays in the current document; `[Section](other.md#section)` opens the target and moves to its heading. ATX and Setext headings use GitHub-style slugs derived from visible inline text: lowercase, punctuation removed, whitespace replaced by hyphens, and duplicate suffixes `-1`, `-2`, etc. Heading lookup uses unsaved target text. Relative file links require a named source; same-document fragments also work in unnamed buffers.
+
+External URL schemes/network paths are rejected; this action never launches a browser or shell. Numeric HTML entities and common named entities (`amp`, `lt`, `gt`, `quot`, `apos`, `nbsp` and their supported aliases) are decoded; other recognized named entities report an unsupported-entity error rather than guessing. Unicode slugs/reference matching use standard-library case conversion, not a complete Unicode case-fold/category table.
+
+`g` waits for `f`, shows in status, and Escape cancels. Other input cancels the prefix and follows ordinary input handling. A configured Normal `g` binding overrides this built-in prefix. Custom bindings use the generated action:
+
+```ruby
+config.bind "leader f", config.core.follow_link
+```
+
 ## Syntax highlighting
 
 Buffers highlight automatically using [Tree-sitter](https://tree-sitter.github.io/tree-sitter/) and compiled-in grammar/query packages. The selected language set is Rust, Ruby, Python, JSON, Bash, Makefile, Markdown, JavaScript/JSX, TypeScript/TSX, HTML, CSS, YAML, TOML, C, C++, and Go. Detection uses filename/extension or the in-memory first-line shebang, including common special filenames such as Makefile, Gemfile, and Cargo.lock; no file reread occurs. Unsupported formats use the normal foreground. The detected language appears in status, and save-as redetects it.