Change detection for text is more painful after text rework

> With the new text stuff, one thing that seems a little rough is that you may have a Text component (with text) or a Text2d or several children with spans. So if you need to "do something when text changes" you have a bunch of different places you have to look for the actual string. With spans, you also have to check the parent if you need components there (like narrowing markers, etc).

> This makes doing change detection on text (for things like "if the text changed, re-localize it") a bit messy. It looks like I'm going to need, for any particular case, multiple systems that cover "all the ways there could be a string squirreled away in there"

- Posted by @brandon-reinhart on [Discord](https://discord.com/channels/691052431525675048/743663673393938453/1293716180829343857)

@ItsDoot and I feel that this could probably be solved with a nice custom SystemParam type that gathers and presents this information.

Start by reviewing the Text, Text2d, and span-related components described in the issue, along with the systems that inspect their strings. The proposed direction is a custom SystemParam that gathers text and relevant parent components; done should provide one consistent way to detect text changes across these cases, but the exact API and tests are not specified.

Written by the indexing model from the issue text.