Renderer should not rerender similar non-collapsed selection.

[f1ames]

See https://github.com/ckeditor/ckeditor5-typing/issues/87 for inital discussion.

There are some cases in which selection changes (the start/end position), but visually it is the same. For example:
<p><em>Text{1}</em></p>
and
<p><em>Text1[1</em>]</p>

In such cases, we call it similar selection (basically, it is not the same, but very similar - only start/end container is different but offsets are somehow the same). In those cases the renderer should detect it and do not rerender the selection (because e.g. it breaks composition sometimes - https://github.com/ckeditor/ckeditor5-typing/issues/87).

This applies only to non-collapsed selection for now.

For collapsed selection it may break a few things, e.g. inserting empty <strong></strong> (with Ctrl/Cmd + b). The selection here is fixed and moved inside empty tag. It is a similar selection so it would not be rendered which is an invalid behavior.

[oskarwrobel]

I hope it will fix this: https://github.com/ckeditor/ckeditor5-engine/issues/880

[f1ames]

Seems like #4022 is very similar issue, so it may get fixed.

[f1ames]

Created a PR ckeditor/ckeditor5-engine#887.