Remove deprecated `Sources` type in favor of `SourcesField` (#13439)
Remove deprecated `Sources` type in favor of `SourcesField` (#13439)

[ci skip-rust]
[ci skip-build-wheels]
benjyw/pants,benjyw/pants,benjyw/pants,pantsbuild/pants,benjyw/pants,benjyw/pants,benjyw/pants,pantsbuild/pants,pantsbuild/pants,pantsbuild/pants,pantsbuild/pants,pantsbuild/pants,pantsbuild/pants,benjyw/pants