un-nixes ur lix, a little

I didn't really go attack the docs because we need to pull a bunch of
PRs. I went looking for strings in the code that called lix nix.

Change-Id: I2138bb4dd239096bc530946b281db7f875195b39

src/libcmd/repl.cc

@@ -186,7 +186,7 @@ ReplExitStatus NixRepl::mainLoop()
         if (state->debugRepl) {
             debuggerNotice = " debugger";
         }
-        notice("Nix %1%%2%\nType :? for help.", nixVersion, debuggerNotice);
+        notice("Lix %1%%2%\nType :? for help.", nixVersion, debuggerNotice);
     }
 
     isFirstRepl = false;