Small inconvenience: END jumps past hidden stuff on next line

Nobody has claimed this yet.

A small quirk with hidden Fountain markup:

With hide markup OFF, and the caret at the beginning of the character name in this text:

```
CHARACTER
_Well?_
```

and you hit END (or cmd + right arrow) the caret, as expected, goes to the right of the word character: `CHARACTER | `

But if you turn it ON, hitting END will send the caret to the next line and past the hidden underscore, like this:

```
CHARACTER
_|Well?_
```

This is also true for asterisks. I'm guessing Beat should rather check where *this* line ends, but now probably checks where *next* begins?

Start by reproducing the caret movement in the Beat editor with hidden markup enabled, using the CHARACTER and _Well?_ example and testing END or Command-Right. Trace the editor's line-end handling for hidden underscores and asterisks. Done means the caret stops at the visible end of the current line rather than moving into hidden markup on the next line.

Written by the indexing model from the issue text.