Error: Unmatched sequence on line 83

After adding this line in my Gemfile and running `bundle install`:

`gem 'jekyll-tidy', group: :jekyll_plugins`

I'm getting an error when running `bundle exec jekyll s`:
`
jekyll 3.7.4 | Error: Unmatched sequence on line 83`

Is there any additional required configuration I'm missing?

Start by reproducing the report with the Gemfile entry, `bundle install`, and `bundle exec jekyll s`, then inspect the reported unmatched sequence on line 83. Determine whether additional configuration is required and document the configuration or change that makes the Jekyll server start successfully.

Written by the indexing model from the issue text.