set pandoc 8 character tab stops for HTML conversion

We add `--tab-stop=8` to all `pandoc(1)` executions in order to set
a better tab stop indentation, especially for tab intended code blocks.

Changed `bin/pandoc-wrapper.sh` VERSION "1.5.3 2024-03-26"
to "1.6 2024-03-31".

Fixed `1991/brnstnd/sorta.README.md` so that the sorta code
is code blocks.

Removed unneeded paragraph group in copyright in `inc/footer.default.html`.

Performed `make www` to perform the above and test under macOS.

1992/imc/index.html

@@ -232,23 +232,23 @@ raster size; not a good idea!).</p>
 <h3 id="options">Options</h3>
 <p>The options of this program are:</p>
 <pre><code>-centre x y  (float x,y) Centre the picture at x+iy in the complex
-             plane (default x=0 y=0)
+                         plane (default x=0 y=0)
 
 
 -factor f    (float f)   Use f pixels per unit of the plane (default
-             f=x/4 where x is the width)
+                         f=x/4 where x is the width)
 
 
 -julia  x y  (float x,y) Draw a julia set. Use x+iy as the constant
-             to add after squaring (default x=0 y=0)
+                         to add after squaring (default x=0 y=0)
 
 -limit  l    (int l)     Use l iterations maximum (default l=128)
 
 -mask   m    (int m)     Use m as a mask in deciding the colour of each
-             pixel (see below) (default m=1)
+                         pixel (see below) (default m=1)
 
 -size   x y  (int x,y)   Produce an x-by-y output (default for raster
-             x=768 y=768; default for text x=63 y=23)
+                         x=768 y=768; default for text x=63 y=23)
 
 -text                    Produce text instead of raster.</code></pre>
 <p>The colour of each point is determined by taking the bitwise AND of the
@@ -272,11 +272,11 @@ standard error to indicate its progress (one dot per pixel line).</p>
 
     You are free to share and adapt this file under the terms of this license:
 
-    Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
+        Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
 
     For more information, see:
 
-    https://creativecommons.org/licenses/by-sa/4.0/
+        https://creativecommons.org/licenses/by-sa/4.0/
 
 -->
 
@@ -339,7 +339,7 @@ standard error to indicate its progress (one dot per pixel line).</p>
 <div class="footer">
   <h2>Copyright and CC BY-SA 4.0 License</h2>
   <p>This file and web page is:</p>
-  <blockquote><p><b>Copyright &copy; 1984-2024 by Landon Curt Noll. All Rights Reserved.</b></p></blockquote>
+  <blockquote><b>Copyright &copy; 1984-2024 by Landon Curt Noll. All Rights Reserved.</b></blockquote>
   <p>You are free to share and adapt this file under the terms of this license:</p>
   <blockquote><b>Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)</b></blockquote>
   <p>For more information, see:</p>