[Feature] Add option to toggle Alternative Command with Double Shift

[MaxMoldmann]

While the Core Plugin Quick Switcher is nice, having an option to use an alternative Community Plugin with more capabilities would be great. E.g. Quick Switcher++ or even better the Omnisearch plugin that finds text in Notes, PDF files and images and supports fuzzy search is great.

For example this new plugin offers to configure the used search plugin: https://www.reddit.com/r/ObsidianMD/comments/1aq5plm/new_plugin_obsidian_beautitab