Exclude listing `pages.en/` when using `scripts/set-alias-page.py` while dry-running

[dmmqz]

While creating the alias page for gh a11y, I noticed that pages.en/ was listed when dry-running. So the output was:

pages/common/gh-a11y.md page would be added
pages.en/common/gh-a11y.md page would be added

The problem with this is pages.en/ is a symlink to pages/. This problem can be solved by checking if the directory is a symlink in the following line:

tldr/scripts/_common.py

Line 105 in 475801f

return [d for d in root.iterdir() if d.name.startswith("pages")]

So this could be changed to:

return [d for d in root.iterdir() if d.name.startswith("pages") and not d.is_symlink()]

If others are in agreement, I'll open a PR to fix this.