You can comment using a hack; check this out:
command `# a comment` \
--longopt1 `# another comment` \
--longopt2 arg \
argument command `# a comment` \
--longopt1 `# another comment` \
--longopt2 arg \
argument command `# a comment` \
# --longopt1 \
--longopt2 arg \
argument
AFAIK there's no hack for this.EDIT: Oh, `# a comment`. Didn't notice that. I'm going to explore it, thanks.