Adds text to the current code block.
Profiling: to A/B isolate cost, try commenting out **one** of these per run (not all at once): - `nested_markdown_render.add(text)` — nested MarkdownGtk.Render / libocmarkdown Parser.add - `this.renderer.code_block_content_updated()` (both call sites below) — parent signal handlers - `GLib.Idle.add` for `scroll_bottom` — scroll work queued every chunk - the `text.contains("\\n")` branch with `resize_widget_callback` — resize on newline chunks
| text |
The text to add |