Implement terminal hyperlinks

[Seanstoppable]

From: rivo/tview#108

I am referring to: https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda

When user use below command in terminal:
echo -e '\e]8;;http://example.com\aThis is a link\e]8;;\a'

In my case, I could get the link in iterm2/terminal app.

[gdamore]

This is interesting -- but I am concerned that it's hard to specify this cleanly, and it will need some kind of new API as the rendering will vary from terminal to terminal. It needs some thought.

[gdamore]

tcell needs to keep a record of what the occupants of every cell are. This is pretty hard to do with this approach, and will put some fairly big challenges on the application code.

[hhirtz]

Hi, i'm writing an IRC client on top of tcell and this is an interesting feature to have when links wrap on multiple lines. How do you want this to be implemented?

tcell needs to keep a record of what the occupants of every cell are.

How about a hyperlink string field in Style:

tcell/style.go

Lines 25 to 29 in 19e1709

	type Style struct {
	fg Color
	bg Color
	attrs AttrMask
	}

and a function to set its value (when url is empty, disable the hyperlink).

func (s Style) Hyperlink(url string) Style {}

[emersion]

This looks like a reasonable design, @hhirtz. I've tried implementing it in #468.