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.

2012/deckmyn/deckmyn.md

@@ -4,7 +4,7 @@
 ## Calling the program
 
 ```sh
-./deckmyn "`cat deckmyn.c`" "`cat musicfile`" > output.pbm
+    ./deckmyn "`cat deckmyn.c`" "`cat musicfile`" > output.pbm
 ```
 
 Then display `output.pbm`.
@@ -86,13 +86,13 @@ musical element of a line is only 2 characters!
 Blank music paper (with G clef):
 
 ```sh
-./deckmyn "`cat deckmyn.c`" "sz sa x  s1 x  s1 x  s1 x  s1 x  s1 "> blank.pbm
+    ./deckmyn "`cat deckmyn.c`" "sz sa x  s1 x  s1 x  s1 x  s1 x  s1 "> blank.pbm
 ```
 
 With an F clef:
 
 ```
-./deckmyn "`cat deckmyn.c`" "KF sz sa x  s1 x  s1 x  s1 x  s1 x  s1 "> blank.pbm
+    ./deckmyn "`cat deckmyn.c`" "KF sz sa x  s1 x  s1 x  s1 x  s1 x  s1 "> blank.pbm
 ```
 
 Notice how only the first staff (or any staff) needs to have the full length.