autoload/find extensions

[teto]

Is your feature request related to a problem? Please describe. I often find myself testing neovim plugins (enabling/disabling) for support reasons etc. For telescope extensions, I have to manually add/remove the code to support its extensions when I enable/disable an extension.

Describe the solution you'd like I would like telescope to autodiscover extensions, it could parse the rtp, follow some standards like for "vim.health".
If it hurts performance. one could have a TelescopeSync command like the :PackerCompile one.

[gegoune]

Or, since extensions are just regular plugins they could register themselves when neovim loads them.

[fdschmidt93]

I'd say we can have this at least as opt-in, PR welcome :)