Did not find a counter proposal where the intent the split the paragraph at that position could have more weight than the intent to append text at the position, so agree now with the proposed OT behaviour.

But IMO the new last branch should be merged with the first, so this check would become
`if (insertTextSpec.position <= splitParagraphSpec.position) {`

Reasoning:
With the proposed patch the order of cases is "before", "after", "same", which is harder to grasp than "before", "same", "after". And given that "before" and "same" get the same treatment, that treatment could be one branch, with both conditions in the same check.