Update base URL regex to work with paths with 'notebook' in them. (#104)

This uses a lazy (non-greedy) regex modifier, to ensure that the first 'notebook' (or 'lab' etc) in the URL is matched
not the last.

Closes #103

stackstac/show.py

@@ -629,7 +629,7 @@ def layers_changed(self, change: dict):
     def base_url_from_window_location(url: str) -> Optional[str]:
         if not url:
             return None
-        if path_re := re.match(r"(^.+)\/(?:lab|notebook|voila)", url):
+        if path_re := re.match(r"(^.+?)\/(?:lab|notebook|voila)", url):
             return path_re.group(1)
         return None