fix: actually truncate over-long commit messages and submodule paths in lists

[Noethix55555]

In branchlist.rs and submodules.rs, the calls to .unicode_truncate(...) return the truncated string slice, but the return value is discarded. As a result the original untruncated string is kept and only "..." is appended, making the displayed entry longer than the available width.

The adjacent branch_name truncation in branchlist.rs already does this correctly (.unicode_truncate(...).0.to_string()). Applied the same pattern to commit_message in branchlist.rs and module_path in submodules.rs.