The text an element of the drawing shows, as a reader should hear it.
Text already drawn is the label as the reader sees it, so it is only
collapsed, never put through plain: a label drawn as <b> is that
text, not markup to strip, and an & in it was already decoded once.
Parameters
element: Element|null|undefined
An element of the drawing, when there is one
Returns string
Its text with whitespace collapsed, or an empty string
The text an element of the drawing shows, as a reader should hear it.
Text already drawn is the label as the reader sees it, so it is only collapsed, never put through plain: a label drawn as
<b>is that text, not markup to strip, and an&in it was already decoded once.