Python: Add non-alert data for lines of code

`py/summary/lines-of-code` is just a port of the C++/JS queries added in:

- https://github.com/github/codeql/pull/5271 (C++)
- https://github.com/github/codeql/pull/5304 (JS)

We are the first to implement the `lines-of-user-code` query, so nothing to
compare with in other languages -- but it makes a lot of sense to do for Python 👍

python/ql/test/query-tests/Summary/also_python_code

@@ -0,0 +1,7 @@
+#!/usr/bin/env python
+
+# although this is actually Python code, it is not included by the extractor by default.
+
+print("this is also code")
+
+print("but just dummy code")