Fixes issue where module name in status bar is not set correctly

Steps to reproduce the issue this PR fixes:

1) disable :lt.objs.langs.julia/connect-on-open in user.behaviors
2) close and reopen LT
3) open two julia files
4) go to the first one opened (left most tab)
5) eval something in it

Expected behaviour:  Module of the current file is shown in the status bar
Actual behaviour:  Module of the other file is shown in the status bar

The fix just ensures the `behavior` that sets the module in the status bar, only updates it for the currently active editor.