No need to install the CKEditor plugin in libraries

Attached patch updates the module's README.txt with more accurate installation instructions.

This looks fine to me.

Since the plugin is packaged with the module (is this allowed?),

I'm curious about this myself. I suppose this is expected to be maintained by the module on the "current" version used, but seems counter to what we'd hope to accomplish with composer dependencies.

I actually had to adapt the original plugin, which was written to use a function from an external helper plugin. I couldn't get CKEditor to load the secondary plugin within Drupal, so made a version of the plugin specifically for this module that includes the necessary function (and a secondary helper function). Not a lot of code at all.

Also, currently working on a couple of issues that are improvements to the plugin itself, including #3159925: ' ' character in summary element breaks ability to normalize word wrapping and #3160326: Support additional elements in the summary.

I did let the original author know that I had adapted his code, which was release under an MIT license, which allows for modification and distribution.

Thanks for the patch, should be able to get this merged into a new release shortly.

Merged in.