The 'importSelection' api did not consider the contentEditable=false elements

[lzf0402]

if before cursor is a contentEditable=false element, set the range to nextSibling

Q	A
Bug fix?	yes
New feature?	no
BC breaks?	yes/no
Deprecations?	yes/no
New tests added?	not needed
Fixed tickets	comma-separated list of tickets fixed by the PR, if any
License	MIT

Description

[Description of the bug or feature]

I use pasteHtml api to insert elements whose contentEditable attribute is 'false'; just like this:

<div contenteditable="false" id="imgcell">
   <img src="xx">
   <span>del img</span>
</div>
<p>test</p>

When the cursor at the start of the 'p' tag, then call 'saveSelection' and blur the editor and then call 'restoreSelection' and 'pasteHtml' to insert other content, it will be fail;

The importSelection api did not consider the contenteditable=false elements

--

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[coveralls]

Coverage decreased (-0.07%) to 94.396% when pulling 507db5b on lzf0402:hotfix_fixselection_180128 into eef3ee0 on yabwe:master.