Martin Brennan fa6b87a1bf
SECURITY: Strip unrendered unicode bidirectional chars in code blocks (#15032)
When rendering the markdown code blocks we replace the
offending characters in the output string with spans highlighting a textual
representation of the character, along with a title attribute with
information about why the character was highlighted.

The list of characters stripped by this fix, which are the bidirectional
characters considered relevant, are:

U+202A
U+202B
U+202C
U+202D
U+202E
U+2066
U+2067
U+2068
U+2069
2021-11-22 10:43:03 +10:00
..