More refactors to prepare for doc-search, including moving unicode support into ext.

luprex/cpp/core/source.hpp

@@ -204,6 +204,13 @@ public:
     //
     eng::string function_docs(const LuaCoreStack &LS, LuaSlot slot);
 
+    // Search the documentation.
+    //
+    // Search all the documentation for the specified substring.
+    // In the result, each line points to a different result.
+    //
+    util::StringVec search_docs(const eng::string &substring);
+
     // Serialize and unserialize a source vector.
     //
     static void serialize_source(const util::LuaSourceVec &sv, StreamBuffer *sb);