Is your enhancement related to a problem? Please describe.
Once WordPress 5.4 is released, we'll want to test Insert Special Characters to see if any incompatibility issues arise.

Describe the solution you'd like

• test Insert Special Characters on WP 5.4
• open issues for any incompatibilities noted in testing
• resolve issues identified in testing
• bump "tested up to" version
• if code changes needed due to incompatibilities, ship a plugin release, otherwise use "Plugin asset/readme update" action to update "tested up to" version on .org repo

Designs
n/a

Describe alternatives you've considered
none

Additional context
none