filter special chars from slugs for email flyout

[adotland]

slug is used as id in dom, leading to css selector syntax errors. use slug filter here to avoid.

ex: Uncaught DOMException: Failed to execute 'querySelector' on 'Document': '#reminder-2021-javaScript-&-friends-conference' is not a valid selector.

[netlify[bot]]

👷 Deploy request for eager-hypatia-82cfde accepted.

🔨 Explore the source changes: f4f14df3f17ff9c6cf3877906103dc80a0403afd

🔍 Inspect the deploy log: https://app.netlify.com/sites/eager-hypatia-82cfde/deploys/611cbf1ff65e9b00075e73c5

[chriscoyier]

sweet thank you!