url plugin: regex blacklist

**Is your feature request related to a problem? Please describe.**

Yes, I keep accidentally triggering the URL opener plugin when I type something that looks like a URL but isn't, specifically when I type something like "something.nvim" which I intend to be a search term, not a URL. This causes the plugin to try to open "something.nvim" as a local file URL, which fails and is not what I want.

**Describe the solution you'd like**

I would like the ability to create a blacklist of regex matches. This would be a list where I can add multiple elements in regex syntax. If a typed string matches any regex in the blacklist, the URL opening plugin should be disabled for that specific input, preventing it from trying to open it as a URL.

**Describe alternatives you've considered**

I have not found any suitable alternatives within the current plugin's settings. I could potentially disable the plugin entirely, but that would defeat its purpose when I do want to open actual URLs.