Support unicode characters at trim_suffix (ellipsis)

Needs test(s) and guidance about if this introduces a security issue.

The patch and MR have different changes - someone needs to:

• Determine which, if either, fix the original issue (using a unicode code as an ellipse).
• Ensure the MR is up-to-date against 2.1.x.
• Add a test.

-mike

I updated the current MR against 2.1.x, added some tests, and decided to use `json_decode()`. I didn't find anything that led me to believe that using `json_decode()` is a security issue, but I did wrap it in an `Html::escape()` to be safe. Tests are passing, needs a review or two.

I also added a `#description` to the formatter config "Suffix" field reading, "Unicode character identifiers of the form \u2026 allowed.".

-mike

Tested locally and was able to convert \u2026 to ...

Anyone want to look at this before I merge?

I have tested that putting "\u2026" in the suffix in the 2.1.x branch and in the issue fork, and verified that without this change, "\u2026" gets appended to the text. With the change, it correctly gets converted to "…".

I've reviewed the code and it looks good to me.

The one thing that occurs to me is that if for some reason you actually want to have "\u" in the suffix, you should be able to do so. I have verified that if you put "\\u" in the suffix, it converts to "\u". I feel it's worth adding a test for that case, so I have added that to TruncateHtmlTest.php. Note that because you can have \" in single quotes, \\ converts to a single slash, so you need \\\\ to represent a double backslash.

*bump* :-)

Thanks to all for helping us get this across the finish line!

-mike

Automatically closed - issue fixed for 2 weeks with no activity.