docs: vcr only set up for markdown (#3339)

- PR branch for testing w/ typescript (@benjamincburns )
- implementation needs better cache invalidation for the cassettes
(@eyurtsev)

---------

Co-authored-by: Ben Burns <803016+benjamincburns@users.noreply.github.com>

docs/_scripts/setup_vcr.py

@@ -0,0 +1,73 @@
+# A list of patterns that, if found in a code block, will cause us to leave that block unchanged.
+import hashlib
+import os
+from textwrap import dedent
+
+preambles = {
+    "python": "vcr_setup_preamble.py",
+    "typescript": "nock_setup_preamble.ts",
+}
+
+
+def _get_python_cassette_init(cassette_name: str, hash_: str) -> str:
+    return dedent(
+        f"""
+        _cassette = HashedCassette('{cassette_name}', '{hash_}')
+        _cassette.__enter__()
+        """
+    )
+
+
+def _get_typescript_cassette_init(cassette_name: str, hash_: str) -> str:
+    return dedent(
+        f"""
+        const _cassette = new HashedCassette("{cassette_name}", "{hash_}");
+        await _cassette.enter();
+        """
+    )
+
+
+def _get_python_cassette_cleanup() -> str:
+    return "_cassette.__exit__()"
+
+
+def _get_typescript_cassette_cleanup() -> str:
+    return "await _cassette.exit();"
+
+
+preamble_inits = {
+    "python": _get_python_cassette_init,
+    "typescript": _get_typescript_cassette_init,
+}
+
+preamble_cleanups = {
+    "python": _get_python_cassette_cleanup,
+    "typescript": _get_typescript_cassette_cleanup,
+}
+
+
+def load_preamble(language: str, code: str, cassette_name: str) -> str:
+    """Load the source code for the preamble for a given language."""
+    _assets_dir = os.path.join(os.path.dirname(os.path.abspath(__file__)), "assets")
+
+    preamble_path = os.path.join(_assets_dir, preambles[language])
+    with open(preamble_path, "r") as f:
+        lines = f.readlines()
+        hash_ = _hash_string(code)
+        lines.append(preamble_inits[language](cassette_name, hash_))
+        return "\n".join(lines).strip()
+
+
+def load_postamble(language: str) -> str:
+    """Load the source code for the postamble for a given language."""
+
+    return preamble_cleanups[language]()
+
+
+def _hash_string(input_string: str) -> str:
+    # Encode the input string to bytes
+    encoded_string = input_string.encode("utf-8")
+    # Create a SHA-256 hash object
+    sha256_hash = hashlib.sha256(encoded_string)
+    # Get the hexadecimal digest of the hash
+    return sha256_hash.hexdigest()