Little (not quick but still dirty) script to be executed once by Pythonista restart (fi in your pythonista_startup.py).
When you tap help in the popup menu of a selected text

After some seconds (function of your iDevice, the number and size of your scripts), you get a list of scripts containing the selected text (case insensitive)

If you select a script, you'll get, like for Pythonista help, a small (webview) window displaying the script as an html with Python syntax highlighting, where occurrences of selected text are also highlighted (in yellow)

If you search has also results in Pythonista help, you'll see both results in the list

The script imports @jonB's swizzle module
You can find this script here