Fix typos from https://svn.boost.org/trac/boost/ticket/9283 and update history.

doc/old_regex.qbk

@@ -18,7 +18,7 @@ documentation is unlikely to be further updated.
 The class RegEx provides a high level simplified interface to the regular 
 expression library, this class only handles narrow character strings, and 
 regular expressions always follow the "normal" syntax - that is the 
-same as the perl / ECMAScript synatx.
+same as the perl / ECMAScript syntax.
 
    typedef bool (*GrepCallback)(const RegEx& expression);
    typedef bool (*GrepFileCallback)(const char* file, const RegEx& expression);