Helping users configure substitutePath using a "strict mode" with helpful error messages

[Red Daly]

I often use rules_go and VS code. Debugging doesn't work off-the-shelf with this setup, and I need to set up "substitutePath." I find it's easy to make errors in the substitutePath config, and I'm left with breakpoints that are silently ignored, etc.

Some ideas:

1) If configured properly, when breakpoints are set, throw an error if the path of the breakpoint isn't found in any of the source files of the executing binary.

2) When such an error is thrown, print a dump of the source files of the binary and try to suggest the proper configuration of subtitutePath such that the breakpoint would be found.

Just some thoughts from a user. I'm not sure if what's suggested is a coherent solution for all scenarios.