feat: make errors more visible with vim.notify

[teto]

the spinner is too discrete and there is a green tick once it finishes so at first I thought the install had succeeded but paying closer attention, the message up/down of it said install had failed

I haven't tested yet. Just putting it out there to see what people think

[github-actions]

Review Checklist

Does this PR follow the Contribution Guidelines? Following is a partial checklist:

Proper conventional commit scoping:

• For example, fix(installer): some installer bugfix

• Pull request title has the appropriate conventional commit prefix.

If applicable:

• Tested
  • Tests have been added.
  • Tested manually (steps in PR description).
• Updated documentation.

[mrcjkb]

I suppose we'd also want this for :Rocks update?

[vhyrro]

Wait, why is there a green tick at the end, if there were errors during the process? I feel like that should be the meat of this problem. I personally feel like a notify and a message in fidget.nvim is slightly too much :p