- Add an OpenWithProgids value. The default value of ".iss" is still being set, though it doesn't appear to have an effect on Windows 11 (the association works without it, and changing it doesn't change the default app).
- Remove OpenWithInnoSetup verb (likely predates the "Open with" menu)
- Unregister before registering. This removes the OpenWithInnoSetup verb on existing installations.
Before the "Open with" menu existed, if an app wanted to add itself to an existing association's context menu without taking over the association completely, it had to modify the ProgID key of whatever app owned the association. To allow for that, we previously were very careful to only delete keys/values under InnoSetupScriptFile that we created.
But there's no longer any need for that. If an app wants an "Open with" item, it should register its own ProgID and add a value under ".iss\OpenWithProgids" linking to it.
