feat: custom trigger events that update the code window

[pocco81]

Fixes #51.

[pocco81]

1c1c46c fixed a small issue that occurred when adding config.events that did not occur before WinScrolled. E.g: I have config.events = { "BufWritePost" }, however if I paste something at the bottom of a file and then try G or :# to go to any of the lines of the thing(s) I pasted without having saved, Codewindow threw an error because those lines did not exist in minimap, and so it failed to update the highlights. This commit implements a simple pcall.

[gorbit99]

Thank you for putting this in, really appreciate it