sourmash sig manifest on zip files yields unusable standalone manifest CSVs

[ctb]

The internal_location is kept as the internal location in the zipfile, rather than the name of the zipfile:

% sourmash sig manifest example.sig.zip -o mf.csv
...
% cat mf.csv | cut -c, -f1
# SOURMASH-MANIFEST-VERSION: 1.0
internal_location
signatures/324074c7287ed934af4fd0a6a459aa30.sig.gz
% sourmash sig describe mf.csv
...
ERROR: Error while reading signatures from 'signatures/324074c7287ed934af4fd0a6a459aa30.sig.gz'.

[ctb]

(it looks like sig collect is the right thing to use here, FWIW. will verify.)

[ctb]

Yes - verified in #3023, updating docs in #3027 which will close this issue.