Misleading error message when GDB is not installed

[Colengms]

Bug type: Debugger

If I don't have GDB installed (yet), and try to use the 'build and debug active file' feature (on Linux, with g++), I get an error message:

However, all I have at this point is tasks.json (not launch.json, which it refs to), and there is no reference to miDebuggerPath in it.

It would be useful if this error message provided enough information to determine that the issue is that GDB needs to be installed.

[Colengms]

Same issue when trying to use clang++. The error message could be more actionable.

[sean-mcmanus]

@elahehrashedi Should this moved to 1.11?