Stray line break in uninstall output

Minor issue: it seems that there should not be a line break after "Removing PATH modifications in startup scripts."
```
% juliaup self uninstall
Do you really want to uninstall Julia? yes
Removing background self update task. Success.
Removing startup self update configuration. Success.
Removing PATH modifications in startup scripts.
Success.
Removing symlinks. Success.
Deleting Juliaup home folder "/Users/x/.julia/juliaup". Success.
Successfully removed Juliaup.
```
I have a hard time seeing where the newline is coming from:
https://github.com/JuliaLang/juliaup/blob/607eb7301428d94f8e14472dd7cec06a622a1cf3/src/command_selfuninstall.rs#L25-L41

Start in src/command_selfuninstall.rs around lines 25-41, as linked in the issue, and reproduce `juliaup self uninstall` to inspect the uninstall output. Trace the message for PATH modifications and verify that the completed output no longer begins on a separate line; confirm the full command output remains correct.

Written by the indexing model from the issue text.