feat: support notification history

[davidosomething]

nvim-notify captures notifications so you can review them in a :Notifications command

would be nice if fidget did the same, maybe in :FidgetNotifications

i plan to use both and my use case would be:

• general notifications to nvim-notify via vim.notify()
• lsp notifications to fidget

[j-hui]

Certainly! This is actually something I already had in mind, but I didn't want to work on it until I decide on the right mechanism for omitting notifications from history (e.g., to ignore progress notifications, which some may consider spammy).

Also I want to do it as a subcommand system (e.g., something like :Fidget history rather than :FidgetHistory).

Also I want to support using Telescope as a notifications viewer (:

[j-hui]

Now, run require("fidget.notification").show_history() to see the history in the echo buffer; or, just use get_history() to get a list of HistoryItems that you can consume or print out yourself. I will create separate issues for the subcommand system and Telescope integration.