Test 'Variable Type Hover'

[weinand]

Test for #8040:

• all platforms - @aeschli

In the latest revision of the VS Code debug protocol Variables can use an optional 'type' attribute. VS Code shows this attribute when hovering over the name of a Variable (hovering over the value of a variable still shows the long version of the value).

The only debug-adpater that supports this right now is mock-debug (from the Marketplace).
Install mock-debug, create a launch config and a markdown file readme.md with some lines of text. Then start debugging.

Verify that the (fake) variables in the Variables view show a type when hovering over the variable's name and that the value is still shown when hovering over the variable's value.

[aeschli]

Tested on Linux, Mac and Windows