Closes #3537.

* substr is deprecated

Hi

'string'.substr() is deprecated

See: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/substr

Using with one argument should be compatible with 'string'.substring()
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/substring

* Use Unicode letter class in TAG_NAME_RE and XML_IDENT_RE
* Tests for using Unicode in XML element names and attribute names.
* Add flag for Unicode regular expression as otherwise use of Unicode character class to have Unicode support in names doesn't work.

* Swift: add existential any keyword

I'm getting contacted occasionally by people who look up the
package's author from npm's registry. Package.json doesn't have a
dedicated 'maintainer' field, so 'author' should work, I think.

Signed-off-by: Josh Goebel <me@joshgoebel.com>

* (enh) lots of small Ruby improvements
* do not scope () as params
* better camel case regex

* Update the pattern regex for the bash language

Fixes: https://github.com/highlightjs/highlight.js/issues/3489 ((bash) keywords with numbers are not recognized)

With the new regex, also numbers INSIDE the pattern is allowed. Before, `a2enmod` would not have been recognized. Now it gets properly recognized.

For the details of the test results see: https://github.com/highlightjs/highlight.js/issues/3489#issuecomment-1050938466

Macaulay2 is a software system devoted to supporting research in
algebraic geometry and commutative algebra.

https://faculty.math.illinois.edu/Macaulay2/

* enh(css): add support for more properties 

Adds background-blend-mode, all the scrollbar-* properties, and the logical versions of all the sizing, padding, border, and margin properties.

Reference:
- https://developer.mozilla.org/en-US/docs/Web/CSS/background-blend-mode
- https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Logical_Properties
- https://developer.mozilla.org/en-US/docs/Web/CSS/scrollbar-width
- https://developer.mozilla.org/en-US/docs/Web/CSS/scrollbar-color
- https://developer.mozilla.org/en-US/docs/Web/CSS/scrollbar-gutter



* Update CHANGES.md

Co-authored-by: Josh Goebel <me@joshgoebel.com>