perf: only search `package.preloaded` and `package.path` for configs

[mrcjkb]

require searches the package.path, the package.cpath, Neovim's runtimepath, etc . It has a total of 6 loaders. To load conigs in lua/<plugins_dir>/lua, we only need the first 2 loaders:

• One that searches package.preloaded (loader cache)
• One that searches package.path

See also: https://pgl.yoyo.org/luai/i/package.loaders

I doubt this has any measurable impact, but it's cleaner than pcall(require, ...) and analysing the error message.

Note: I haven't directly tested this in rocks-config.nvim, but I've tested the logic on modules in my lua directory.

[github-actions[bot]]

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[vhyrro]

LGTM!