Make the build target quickPick editable

If the current makefile configuration fails to a degree that is not able to produce even the targets (this means IntelliSense is gone also) and if that configuration would be actually able to succeed if one particular target would be passed to make (and the user knows it), currently with an empty quick pick the user can't exit from a failure state in the extension (unless defining a new makefile configuration with all the properties of the current makefile configuration and as an argument the extra target).

I'm thinking to make the quick pick editable for such cases.

This is not needed for makefile.buildConfiguration, which comes entirely from the user.
This is not needed for launch configurations (even if they are also a quick pick populated by a dry-run) because their computation would already benefit of the good target being already selected.

I wasn't able to put this in 'triage' and is already placed in 'to do'.

Start by tracing the quick pick used when the Makefile configuration fails, then compare it with makefile.buildConfiguration and launch configuration handling. Done means a user can enter a target in the empty quick pick and recover when that target allows the configuration to succeed, without changing the other configuration flows.