interp: make "type" builtin respect the current $PATH

[theclapp]

Fixes #502.

[theclapp]

Regarding the locale change:

-	os.Setenv("LANGUAGE", "en_US.UTF8")
-	os.Setenv("LC_ALL", "en_US.UTF8")
+	os.Setenv("LANGUAGE", "en_US.UTF-8")
+	os.Setenv("LC_ALL", "en_US.UTF-8")

Without this change, I got failures galore. This didn't used to fail. I think it does now because I upgraded bash to 5.0.16 locally.

I looked at trying to install that locale, or copy the existing one, and came up (mostly) empty. All the UTF8 locales on my system are ...UTF-8 not ...UTF8. Copying the one to the other failed:

# in /usr/share/locale
% sudo cp -rp en_US.UTF-8 en_US.UTF8
cp: cannot create directory 'en_US.UTF8': Operation not permitted

Not sure what you can or should do about that. I assume the current "UTF8" code works for you and everybody else. 🤷‍♂

[mvdan]

Please add the "Fixes" to the commit, because that's what will remain in master. The PR body isn't really relevant.

[mvdan]

I agree this is a good change. Not sure why the old version worked. I think it was a typo of mine.

[theclapp]

Done. PTAL.