Toggle Line Comment selects line if no comment syntax available

[peterflynn]

1. Open a .txt file or some other language where languages.json doesn't define any commenting syntax
2. Place the cursor anywhere and press Ctrl+/

Result: the line gets selected

Expected: nothing happens -- as in Sprint 37 (and Toggle Block Comment still works this way even on master)

[pthiess]

@njx is taking a look at the PR.

[njx]

FBNC to @peterflynn

[peterflynn]

Confirmed fixed