Parserail standardizes heading overflow rules across all renderers

Parserail standardizes heading overflow rules across all renderers

Ops log: Parserail renders the mail rail, and long headings pushed useful email information into the wrong place. The rendered heading had a 50-character cap, so Parserail moved whole trailing sentences into the body instead of cutting them. If the first sentence cannot fit, Parserail throws because it cannot invent a shorter heading. We made every Parserail renderer use the same rule. what parserail does with headings heading fits the cap: stays in heading heading exceeds the cap: sentences move to body first sentence exceeds cap: throws Parserail preserves whole sentences and refuses to invent shorter heading text.