Improve error message for import exception group

[dotku]

Purpose

Improve error message for import exception group

References

#14056 (#14056)

[AA-Turner]

How does this improve the status quo?

A

[dotku]

Just make it more friendly error message reading according to the related issue.

Won't able to find the module doesn't means the module is not exited.

[flying-sheep]

Yeah, as I said in #14056: “no module named thing” doesn’t necessarily make sense.

Imagine thing is very much a module in sys.path, but its import failed because of some exception during module execution (ImportError or otherwise). Then “no module named thing” is just wrong, while “could not import thing” is correct and therefore not confusing.