Unicode characters are not picked up by UDL

[RiabikovR]

Description of the Issue

When "「" and "」" are used to open and close a delimiter in a user defined language, said delimiters are not highlighted in the text.
I assume it also applies to other unicode characters and fields other than delimiters.

Steps to Reproduce the Issue

1. Create a user defined language
2. Add a new delimiter, opened by "「" and closed by "」", styled in italic
3. Paste "「Lorem ipsum」" into a sample document

Expected Behavior

The line "「Lorem ipsum」" is displayed in italic.

Actual Behavior

The line "「Lorem ipsum」" is displayed in default text style.

Additionally, UDL should probably be expanded to recognize unicode character codes the same way it currently works with newline.
Something like ((u0123)) or '\u0123.