Better quote splitting when first sentence is >240 characters

[ndrezn]

Right now, captions are generated by concatanating sentences until the 240 character limit is reached. This works fine, but occassionally the first sentence is >240 characters and there's no prose attached to the tweet. In this circumstance, the caption should be tokenized by word rather than character and split in the middle of the sentence, with the rest of the sentence added to the reply caption. See https://en.wikipedia.org/wiki/Template:POTD/2022-09-26 for an example.