improved indentation and whitespace for markdown code blocks

All code blocks in markdown have been intended by at least 4 spaces.

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 from "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`.

Fixed excess whitespace after list Author on entry `index.html` page.

Changed `bin/output-index-author.sh` VERSION from "1.5.2 2024-03-26"
to "1.6 2024-03-31".

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

TODO: Fix the problem of the initial line of code being extra intended.
TODO: Fix excess whitespace around code that is inline.

2004/anonymous/README.md

@@ -1,14 +1,14 @@
 ## To build:
 
 ```sh
-make
+    make
 ```
 
 
 ## To use:
 
 ```sh
-./anonymous 'foo' > bar.pgm
+    ./anonymous 'foo' > bar.pgm
 ```
 
 Now open the output using your favourite
@@ -22,7 +22,7 @@ images.
 ## Try:
 
 ```sh
-./try.sh
+    ./try.sh
 ```
 
 NOTE: technically the text is supposed to be in all lower case but the script
@@ -108,8 +108,8 @@ inscription](https://www.glyphweb.com/arda/r/ringinscription.html) to
 the file `ring.pgm`:
 
 ```sh
-./anonymous "ash nazg durhbatuluhk, ash nazg gimbatul, \
-    ash nazg thrakatuluhk, agh burzhumh-ishi krimpatul." >ring.pgm
+    ./anonymous "ash nazg durhbatuluhk, ash nazg gimbatul, \
+	ash nazg thrakatuluhk, agh burzhumh-ishi krimpatul." >ring.pgm
 ```
 
 The source code assumes the ASCII character set; also, due to space