Allow extensions to add coloured markers in the gutter similar to source control

[DanTup]

The source control functionality currently renders nice coloured markers down the gutter. It'd be nice if this functionality was available to extensions that aren't source control (for example code coverage).

[alexdima]

This is something that could be added to the text editor decoration API, specifically as a new property to ThemableDecorationRenderOptions

[eamodio]

@DanTup I'm assuming here, you are looking for more than just an indicator though right? You'd want them clickable like the SCM gutters?

[DanTup]

The feature I wanted this for was ditched, so this isn't a need for me now. However it was intended for something similar to code coverage. The idea was to mark lines that are hot-reloaded into a running app, and then change the colour as the execute (it was intended to help understand if changes you've made and hot reloaded were not being run).

Clicking probably wouldn't have been necessary (for this, though maybe they'd be useful for others?), though tooltips would've been good (to explain what the two different colours meant).

[Jack2104]

I have a need for this right now too (with them being clickable). I want the user to be able to mark areas of code and have those marked code segments be timed.

@eamodio or @alexdima - will this ever be added?