Text Examples

## What problem does this solve or what need does it fill?

We have examples of how to use the UI specific `Text` API, and examples of how to use the 2d specific `Text2d` API, but not examples of how to use `bevy_text`'s own API's to implement custom text features.

## What solution would you like?

Add a `text` example directory, with some `bevy_text` specific examples.

## What alternative(s) have you considered?

We could just be happy with the `2d` and `ui` examples that use text.

Review the existing UI-specific Text and 2D-specific Text2d examples, then inspect the bevy_text API to identify suitable custom text features to demonstrate. Done means adding a text example directory with bevy_text-specific examples rather than relying only on the existing 2d and ui examples.

Written by the indexing model from the issue text.