fix: drop trailing slash from example_dirs symlink targets

[KiSetsuFu-PuLiN]

The four examples/example_dirs symlinks pointed at ../../example_dirs/ — with a trailing slash. On Windows, libgit2 (the git library backing cargo and many other tools) strips the trailing slash when reading a symlink target, so it reported the worktree as modified while git status reported it clean. This makes tools like cargo clippy --fix refuse to run on a clean, freshly checked out worktree:

error: the working directory of this package has uncommitted changes, and `cargo fix` can potentially perform destructive changes; ...