repl: Add ability to evaluate Markdown code blocks (#15100)

This adds the ability to evaluate TypeScript and Python code blocks in
Markdown files.

cc @rgbkrk 

Demo:


https://github.com/user-attachments/assets/55352de5-68f3-4aef-920a-78ca205651ba



Release Notes:

- N/A

---------

Co-authored-by: Nathan <nathan@zed.dev>
Co-authored-by: Antonio <antonio@zed.dev>

Cargo.lock

@@ -8678,6 +8678,7 @@ dependencies = [
  "image",
  "indoc",
  "language",
+ "languages",
  "log",
  "multi_buffer",
  "project",
@@ -8689,6 +8690,9 @@ dependencies = [
  "smol",
  "terminal_view",
  "theme",
+ "tree-sitter-md",
+ "tree-sitter-python",
+ "tree-sitter-typescript",
  "ui",
  "util",
  "uuid",