fix lexer regex -ugly hack to fix pcre strictness with ranges

an upgrade to php7.3/libpcre and ... this breaks. this is an ugly
hack, but it gets wiki content back.

public_html/inc/parser/lexer.php

@@ -160,6 +160,8 @@ class Doku_LexerParallelRegex {
             $cnt = count($this->_patterns);
             for ($i = 0; $i < $cnt; $i++) {
 
+                if ($this->_patterns[$i] == '\\\\\\\\\\w+?(?:\\\\[\\w-$]+)+')
+                  $this->_patterns[$i] = '\\\\\\\\\\w+?(?:\\\\[\\$-w]+)+';
                 /*
                  * decompose the input pattern into "(", "(?", ")",
                  * "[...]", "[]..]", "[^]..]", "[...[:...:]..]", "\x"...