Update TSS "file loaded" check

The TSS confirmation message when a file has been loaded got a little change in a new version.

The emacs plugin was still checking for the old message, which led to a long loading time. I updated this check so that the plugin detects both message formats.

I wanted to test my changes in the unit tests, but I couldn't find tenv... Is this a custom library?

Oh, and maybe the slowness reported by @skvsree comes from this kind of incompatibility...