Update installation script to use Wait+Screen for virtual environment readiness

Author: httpdss

docs/vhs/install.tape

@@ -69,7 +69,7 @@ Sleep 5
 Type "source .venv/bin/activate" Enter
 Sleep 5
 Type "pip install git+https://github.com/httpdss/struct.git" Enter
-Wait /venv/
+Wait+Screen /venv/
 Sleep 2
 Type "# STRUCT is now installed and ready to use" Enter
 Type "struct list" Enter