Fix a bug in function registry, improve docs

luprex/core/cpp/util.hpp

@@ -70,6 +70,9 @@ StringVec split(const std::string &s, char sep);
 // Split a string into multiple strings using \r or \n
 StringVec split_lines(const std::string &s);
 
+// Split a string into multiple lines using |, remove any leading blank line.
+StringVec split_docstring(const std::string &s);
+
 // Join multiple strings into one string
 std::string join(const StringVec &strs, std::string sep);