Describe the issue

#define FOO 10'000

is valid code, using ' as a digit separator. Highlight.js incorrectly treats it as a beginning of a string.

Which language seems to have the issue?

I tested C and C++, both get it wrong.

Are you using highlight or highlightAuto?

No clue. I originally noticed the issue while sending code over Discord and confirmed it again with your demo. I did select the language manually in both cases.

Expected behavior

The ' character should be treated as part of the number.

Additional context

Support for this separator has been around in C++ since C++14, but it's relatively new in C, added in C23.