Clarify Pallene vs Titan relation in README
Fixes
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Pallene is a statically typed, ahead-of-time-compiled sister language to
-[Lua](https://www.lua.org), with a focus on performance. It is also a friendly
-fork of the [Titan](https://www.github.com/titan-lang/titan).
+[Lua](https://www.lua.org), with a focus on performance. It is also a
+[friendly fork](http://lua-users.org/lists/lua-l/2018-09/msg00255.html) of the
+[Titan](https://www.github.com/titan-lang/titan) language.
Pallene is intended for writing performance sensitive code that interacts with
Lua, a space that is currently filled by C modules and by LuaJIT. Compared to
