Implement GlyphMarginWidgets

[joyceerhl]

Fixes #114776
Fixes #183400
Part of #179725

Test adoption for the arrow revert widget (not checked in with this PR):

glyph-widgets.mp4

[alexdima]

Looking pretty good and in the right direction! I pushed a change to do the lane count computation only once per frame. I also left a couple of comments, plus there are a couple of problems that I've spotted for which I didn't add comments, as I didn't digg deeper to see what are the root causes:

• enable "typescript.referencesCodeLens.enabled": true
• observe how the breakpoints margins are rendered one line above than before
• observe also that sometimes the breakpoints cannot be removed:

Kapture.2023-06-13.at.15.04.55.mp4

[joyceerhl]

Looked into the off-by-one issue some, it looks like whitespace added by codelenses, as well as the peek view widgets, are not included in the calculation for getVerticalOffsetForLineNumber even when accounting for viewzones:

vscode/src/vs/editor/browser/viewParts/glyphMargin/glyphMargin.ts

Line 452 in fda41b8

renderedWidget.domNode.setTop(ctx.getVerticalOffsetForLineNumber(renderedWidget.lineNumber, true));

I probably need a different way to calculate the top offset for each decoration, will do some digging

[joyceerhl]

Fixed!

glyph-widgets-fix.mp4