call one heavy method instead of 3 in a string

[lucianosousa]

Looks like html_safe is called in a empty string just to use safe_concat in the next two string merges.
We can ignore these two calls - and html_safe in favor of use raw in the method output.

[rails-bot]

Thanks for the pull request, and welcome! The Rails team is excited to review your changes, and you should hear from @eileencodes (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

Please see the contribution instructions for more information.

[eileencodes]

Hey @lucianosousa thanks for the PR! Does this change result in any performance improvements? If you believe it does can you use github.com/evanphx/benchmark-ips to show the difference before and after?

[rafaelfranca]

Thank you for the pull request but this may open doors to a possible security issue. It didn't introduced the issue in this commit but it can introduce if the code is changed in the future to concatenate a unsafe string. safe_concat always make sure that the result string is safe while raw blindly mark the string as safe.