Add nbb.core/invoked-script fn

[bolivier]

Introduces nbb.core/invoked-script that outputs an absolute path based on the file passed to nbb, either literally or with -m

The rationale is to be able to use

(if (= *file* (invoked-script))
  :foo
  :bar)

to only run things when the script is invoked, not at a repl.

The tests verify that *file* and (invoked-script) are present and the same when used with -m and passing the plain script.

Please answer the following questions and leave the below in as part of your PR.

• I have read the developer documentation.

• This PR corresponds to an issue with a clear problem statement.

• This PR contains a test to prevent against future regressions

• I have updated the CHANGELOG.md file with a description of the addressed issue.

[borkdude]

I don't think we need to set invoked-script for -m. This also doesn't happen in babashka:

borkdude@m1 /tmp $ echo '(ns foo) (defn -main [& args] (prn (System/getProperty "babashka.file")))' > foo.clj
borkdude@m1 /tmp $ bb -cp . -m foo
nil

The reason it's not set is that invoked-script or (System/getProperty "babashka.file") is for causing side effects when the script is directly invoked.

[bolivier]

It seems like the same use cases would apply to both situations, no?

[borkdude]

No, since a -main function doesn't cause any side effects, unless you execute it manually, which is not the case when you invoke nbb with -m.

[borkdude]

Tests are failing, but the rest looks good to me

[borkdude]

Tests still fail, I think you need a quote around the vector in require. Perhaps consider running tests locally.

[borkdude]

Cool! And the last bit, can you update the changelogs? Then I'll merge

[borkdude]

Thanks!