Why doesn't use `.sr-only` in spinner?
Created by: ysds
https://twbs-bootstrap4.netlify.com/docs/4.1/components/spinners/#about
For accessibility purposes, ...., using a text hiding technique to prevent it from rendering on screen.
Text hide technique is not a modern approach (#24890 (closed)). IMO we should use .sr-only
to hide Loading...
text:
<div class="spinner-border" role="status"><span class="sr-only">Loading...</span></div>