Remove trailing commas in templates

[fertapric]

I think there are pros and cons about trailing commas, but this change is consistent with the formatter.

[josevalim]

❤️ 💚 💙 💛 💜

[eksperimental]

May I ask what are the pros.

[OvermindDL1]

May I ask what are the pros.

@eksperimental Seems off-topic here and it's been discussed elsewhere, but the most common pro's are consistency with all other list elements and easy copy/pasting (like say the hex.pm website had a , at the end of it, then you could just copy/paste the thing into a new line and it wouldn't matter if it was at the end or not or needing to remember to add a comma to another list element or not, it would just work (I forget adding a comma quite often when adding a dependency as one example). I use trailing commas for both these reasons.

[eksperimental]

Sorry, I meant what are the cons

[OvermindDL1]

Sorry, I meant what are the cons

Inconsistency with the existing formatter style? I honestly don't see cons with using trailing commas on element-by-line list/tuple/arg/map formatting personally, but do see lots of pros.