[TxMt] Javascript bundle only creates block comments with cmd-/

Hi all - Something's gone wonky with my Javascript bundle (and only that one, as far as I can tel)l. Every time I hit cmd-/ to comment/uncomment some text, it uses an unindented block comment instead of the double-slash single line comment I expect. ("/* */", rather than "// ")

So: " this line" becomes "/* this line*/" when what I want and expect is " // this line"

I suspect this has to do with some way I've edited the language bundle incorrectly. Does anyone know A) how I could fix this particular issue, or B) how I could remove all my changes to the Javascript bundle and revert simply to the repo version?

Cheers, Evan