Doc: fix import of asdl.py when called from outside Doc/. (GH-21529)
diff --git a/Doc/tools/extensions/asdl_highlight.py b/Doc/tools/extensions/asdl_highlight.py
index 7d2ef01..b1989e5 100644
--- a/Doc/tools/extensions/asdl_highlight.py
+++ b/Doc/tools/extensions/asdl_highlight.py
@@ -1,6 +1,9 @@
import os
import sys
-sys.path.append(os.path.abspath("../Parser/"))
+from pathlib import Path
+
+CPYTHON_ROOT = Path(__file__).resolve().parent.parent.parent.parent
+sys.path.append(str(CPYTHON_ROOT / "Parser"))
from pygments.lexer import RegexLexer, bygroups, include, words
from pygments.token import (Comment, Generic, Keyword, Name, Operator,