Update warning to be correct for library update

The warning we have here is not accurate for PCRE2, since it supports
more Unicode properties than PCRE.

See also <PCRE2Project/pcre2#39> and
<https://www.pcre.org/current/doc/html/pcre2pattern.html>.

Author: kopecs

docs/writing-rules/rule-syntax.md

@@ -155,7 +155,7 @@ This rule looks for usage of the Python standard library functions `hashlib.md5`
 The `pattern-regex` operator searches files for substrings matching the given [PCRE2](https://www.pcre.org/current/doc/html/pcre2pattern.html) pattern. This is useful for migrating existing regular expression code search functionality to Semgrep. Perl-Compatible Regular Expressions (PCRE) is a full-featured regex library that is widely compatible with Perl, but also with the respective regex libraries of Python, JavaScript, Go, Ruby, and Java. Patterns are compiled in multiline mode, for example `^` and `$` matches at the beginning and end of lines respectively in addition to the beginning and end of input.
 
 :::caution
-PCRE2 supports only a [limited number of Unicode character properties](https://www.pcre.org/current/doc/html/pcre2pattern.html#uniextseq). For example, `\p{Egyptian_Hieroglyphs}` is supported but `\p{Bidi_Control}` isn't.
+PCRE2 supports [some Unicode character properties, but not some Perl properties](https://www.pcre.org/current/doc/html/pcre2pattern.html#uniextseq). For example, `\p{Egyptian_Hieroglyphs}` is supported but `\p{InMusicalSymbols}` isn't.
 :::
 
 #### Example: `pattern-regex` combined with other pattern operators