Reformat inclusion of COPYING.txt into license.txt. Include as non-literal text. This removes the need to scroll to read the license. Also makes the hyperlinks work. Colorize the background under the included file to allow easy identification of part of license.txt that is from COPYING.txt like we used to have with the literal inclusion. Had to add raw html to create a div to add the color. Using .. container:: didn't work since indenting .. include:: caused sphinx to throw errors on the headers in COPYING.txt. Reformated COPYING.txt to eliminate unwanted indentation caused by blockquote being triggered.

--- a/doc/_static/style.css	Mon May 29 20:09:40 2023 -0400
+++ b/doc/_static/style.css	Mon May 29 20:29:04 2023 -0400
@@ -454,3 +454,8 @@
 ul.multicol > * {
   margin-block-start: 0; /* remove spacing added by * + * here */
 }
+
+div.file_insert { /* use to insert COPYING into license.txt */
+    background: #f3f1cc;
+    padding-inline: 0.5em;
+}