Completion details should have syntax highlighting

[jmagaram]

This is a big annoyance I've just come to accept in Visual Studio and VS Code and I suspect many other developers have too. The pop-up windows that explain function arguments and various other situations are very difficult to parse because they just wrap text wherever and no keywords are highlighted. In other words, the pop-up windows show code in a way that we would never accept in our source files. Here is an example showing what is expected for javascript array reduce. From this pop-up it is extremely difficult to tell how many arguments the function takes and of what kind. I'd really like to see each argument on its own line. If an argument is a function, then show each of the arguments to that function indented on its own line. Maybe have some highlighting too. I'm not sure what the right solution is, but I do know the current behavior makes it really tough to figure out what is going on.

[octref]

Here is the image

I also found this a very lacking experience.

[octref]

The issue is detail is just a string, meant for less-prominent info. We might allow string | MarkupContent in the future for detail to have code blocks.

[KamasamaK]

Also see #34188

[octref]

Closing as duplicate of #34188.