Add list_repo_pkgs to modules/pkgng.py

[Jsollvander]

What does this PR do?

See discussion for details.

What issues does this PR fix or reference?

Fixes #70317.

Previous Behavior

salt-call pkg.install zrepl test=true
local:
    ----------

New Behavior

salt-call pkg.install zrepl test=true
local:
    ----------
    zrepl:
        ----------
        new:
            0.7.0_8
        old:

Merge requirements satisfied?

[NOTICE] Bug fixes or features added to Salt require tests.

• Docs
• Changelog - https://docs.saltproject.io/en/master/topics/development/changelog.html
• Tests written/updated

Commits signed with GPG?

Yes

This is my first time contributing code here. Let me know if I need to fix anything.

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[twangboy]

1. Bug in Output Parsing (ValueError: not enough values to unpack):

Lines 2380–2382:

for line in salt.utils.itertools.split(out, "\n"):
    pkg, version = line.strip().rsplit("-", 1)
    ret.setdefault(pkg, []).append(version)

Problem: If FreeBSD's pkg search outputs an empty line, a malformed line, or if out is empty, line.strip().rsplit("-", 1) will raise a ValueError when unpacking into pkg, version. Additionally, package names or version strings could theoretically lack a -.

Fix: Guard against empty lines and ensure rsplit produced two elements:

for line in salt.utils.itertools.split(out, "\n"):
    line = line.strip()
    if not line or "-" not in line:
        continue
    pkg, version = line.rsplit("-", 1)
    ret.setdefault(pkg, []).append(version)

2. Inaccurate Docstring Example:

The docstring example (lines 2340–2345) shows Ubuntu/Debian version strings (4.3-14ubuntu1.1). Because pkgng is specific to FreeBSD, updating the example to reflect FreeBSD package versions (e.g., bash-5.2.21, nginx-1.26.1,2) would keep documentation accurate.

3. Missing Unit Test for Multiple Arguments / Globs:

test_list_repo_pkgs currently only tests passing a single package ("vim"). Adding a unit test that verifies passing multiple package arguments ("vim", "zsh") or empty output parsing edge cases would ensure full coverage of the execution path.