Document preference for "{{placeholder}}" instead of {{"placeholder"}}

[kbdharun]

I did a search in the repo and it seems like this is the preferred form ("{{arg}}" instead of {{"arg"}}), but there are still a few cases of {{"arg"}}. Is this style preference documented anywhere?

I don't think we have documented it yet, but yes we do prefer "{{placeholder}}".

Originally posted by @kbdharun in #12603 (comment)