parsing: option to [end] to terminate parsing even if there is further input

[wezm]

I use time in my rsspls project (thanks!). It's a tool that uses CSS selectors to extract parts of web pages and build an RSS feed from them. time is used for parsing dates that will become the published date of the RSS item. In https://github.com/wezm/rsspls/issues/46 the element in the HTML that contains the date actually has two dates in it like this:

<td><td tabindex="0" role="cell" class="periodo-pubblicazione date">31/05/2024<br>  15/06/2024</td>

Which is "31/05/2024 15/06/2024" when extracted. We'd like to be able to parse the first date. This is similar in nature to https://github.com/time-rs/time/issues/471 but my idea is to add a modifier to the end component that allows it to be used even when all the input has not been consumed. This would allow using a format description like [day padding:zero]/[month padding:zero]/[year][end eof:false]

I'd be open to implementing this if it seems reasonable.