Fix source annotation in pip compile annotation-style=line output

[blueraft]

Summary

Fixes a small discrepancy between the pip compile outputs for annotation-style=split and annotation-style=line commands.

Problem

Consider the following pyproject.toml file.

$ cat pyproject.toml
[project]
name = "uv_test"
dynamic = ["version"]
dependencies = ["click"]

Running uv pip compile with annotation-style=split on uv 0.1.44 version yields the following:

❯ uv pip compile pyproject.toml --annotation-style=split
Resolved 1 package in 2ms
# This file was autogenerated by uv via the following command:
#    uv pip compile pyproject.toml --annotation-style=split
click==8.1.7
    # via uv-test (pyproject.toml)

However, running uv pip compile with annotation-style=line doesn't include source info for root level dependencies.

❯ uv pip compile pyproject.toml --annotation-style=line
Resolved 1 package in 1ms
# This file was autogenerated by uv via the following command:
#    uv pip compile pyproject.toml --annotation-style=line
click==8.1.7

With this PR:

❯ ../target/debug/uv pip compile --annotation-style=line pyproject.toml
Resolved 1 package in 6ms
# This file was autogenerated by uv via the following command:
#    uv pip compile --annotation-style=line pyproject.toml
click==8.1.7              # via uv-test (pyproject.toml)

This also now matches pip-tools output:

❯ pip-compile --annotation-style=line pyproject.toml
#
# This file is autogenerated by pip-compile with Python 3.12
# by the following command:
#
#    pip-compile --annotation-style=line pyproject.toml
#
click==8.1.7              # via uv_test (pyproject.toml)

Test Plan

cargo test

[charliermarsh]

Thanks!