Output of "Has alternative text" could be misleading

[mattgarrish]

The last "if" statement in the nonvisual reading section will output "Has alternative text" if any of the following features are set: long descriptions, alternative text, described math, or transcripts. This occurs regardless of whether text alternatives are provided for all non-textual content.

But "alternative text" is closely tied to alt text. Saying there is alternative text if all the book has is a transcript for an audio clip feels weird. You could even get this output if there is a transcript but all the images haven't been described, which would be even weirder.

If we're just trying to capture alt text, then we shouldn't be using all of what is captured by textual_alternatives. Conversely, if we're just trying to say that there are some text equivalents for non-textual content, it would be better to use similar naming to the variable (e.g., "Has text alternatives").